Making Java more dynamic: runtime code generation for the JVM
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- Ellen Williams
- 6 years ago
- Views:
Transcription
1 Making Java more dynamic: runtime code generation for the JVM
2 The talk was way too high-level. I wish the speaker would have explained more technical details!
3 This was way too low-level. I did not understand what this talk was about. The talk was way too high-level. I wish the speaker would have explained more technical details!
4 The talk was way too high-level. I wish the speaker would have explained more technical details! This was way too low-level. I did not understand what this talk was about. Perfect level. Great talks!
5 @interface Secured { String user(); class UserHolder { static String user = "ANONYMOUS";
6 @interface Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; class Service = "ADMIN") void deleteeverything() { // delete everything...
7 interface Framework { <T> Class<? extends T> secure(class<t> Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; class Service = "ADMIN") void deleteeverything() { // delete everything...
8 interface Framework { <T> Class<? extends T> secure(class<t> Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; class Service = "ADMIN") void deleteeverything() { // delete everything...
9 interface Framework { <T> Class<? extends T> secure(class<t> Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; class Service = "ADMIN") void deleteeverything() { // delete everything...
10 interface Framework { <T> Class<? extends T> secure(class<t> Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; depends on does not know about class Service = "ADMIN") void deleteeverything() { // delete everything...
11 interface Framework { <T> Class<? extends T> secure(class<t> type); discovers at Secured { String user(); class UserHolder { static String user = "ANONYMOUS"; depends on does not know about class Service = "ADMIN") void deleteeverything() { // delete everything...
12 class Service = "ADMIN") void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); // delete everything... redefine class (build time, agent) class Service = "ADMIN") void deleteeverything() { // delete everything...
13 class SecuredService extends Service void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); super.deleteeverything(); create subclass (Liskov substitution) class Service = "ADMIN") void deleteeverything() { // delete everything...
14 source code
15 source code javac scalac groovyc jrubyc 0xCAFEBABE byte code
16 source code javac scalac groovyc jrubyc 0xCAFEBABE byte code class loader interpreter JIT compiler JVM
17 source code javac scalac groovyc jrubyc creates 0xCAFEBABE byte code class loader interpreter JIT compiler JVM
18 source code javac scalac groovyc jrubyc reads creates 0xCAFEBABE byte code class loader interpreter JIT compiler JVM
19 source code javac scalac groovyc jrubyc reads creates 0xCAFEBABE byte code class loader runs interpreter JIT compiler JVM
20 Isn t reflection meant for this? class Class { Method getdeclaredmethod(string name, Class<?>... parametertypes) throws NoSuchMethodException, SecurityException; class Method { Object invoke(object obj, Object... args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException;
21 Isn t reflection meant for this? class Class { Method getdeclaredmethod(string name, Class<?>... parametertypes) throws NoSuchMethodException, SecurityException; class Method { Object invoke(object obj, Object... args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException; Reflection implies neither type-safety nor a notion of fail-fast. Note: there are no performance gains when using code generation over reflection! Thus, runtime code generation only makes sense for user type enhancement: While the framework code is less type safe, this type-unsafety does not spoil the user s code.
22
23 Java source code Java byte code int foo() { return 1 + 2;
24 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD
25 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD operand stack
26 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD operand stack 1
27 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD operand stack 2 1
28 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD operand stack 3
29 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD IRETURN operand stack 3
30 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD IRETURN operand stack
31 Java source code Java byte code int foo() { return 1 + 2; ICONST_1 ICONST_2 IADD IRETURN 0x04 0x05 0x60 0xAC operand stack
32 ASM / BCEL Javassist cglib Byte Buddy MethodVisitor methodvisitor =... methodvisitor.visitinsn(opcodes.iconst_1); methodvisitor.visitinsn(opcodes.iconst_2); methodvisitor.visitinsn(opcodes.iadd); methodvisitor.visitinsn(opcodes.ireturn);
33 ASM / BCEL Javassist cglib Byte Buddy visitor API tree API MethodVisitor methodvisitor =... methodvisitor.visitinsn(opcodes.iconst_1); methodvisitor.visitinsn(opcodes.iconst_2); methodvisitor.visitinsn(opcodes.iadd); methodvisitor.visitinsn(opcodes.ireturn); MethodNode methodnode =... InsnList insnlist = methodnode.instructions; insnlist.add(new InsnNode(Opcodes.ICONST_1)); insnlist.add(new InsnNode(Opcodes.ICONST_2)); insnlist.add(new InsnNode(Opcodes.IADD)); insnlist.add(new InsnNode(Opcodes.IRETURN));
34 ASM / BCEL Javassist cglib Byte Buddy int foo() { return 1 + 2;
35 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + ""
36 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary )
37 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary ) Specifically: Security problems!
38 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary ) Specifically: Security problems! Makes debugging difficult (unlinked source code, exception stack traces)
39 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary ) Specifically: Security problems! Makes debugging difficult (unlinked source code, exception stack traces) Bound to Java as a language
40 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary ) Specifically: Security problems! Makes debugging difficult (unlinked source code, exception stack traces) Bound to Java as a language The Javassist compiler lags behind javac
41 ASM / BCEL Javassist cglib Byte Buddy "int foo() {" + " return 1 + 2;" + "" Strings are not typed ( SQL quandary ) Specifically: Security problems! Makes debugging difficult (unlinked source code, exception stack traces) Bound to Java as a language The Javassist compiler lags behind javac Requires special Java source code instructions for realizing cross-cutting concerns
42 ASM / BCEL Javassist cglib Byte Buddy class SecuredService extends Service void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); super.deleteeverything();
43 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); super.deleteeverything(); interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
44 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); super.deleteeverything(); interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
45 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { if(!"admin".equals(userholder.user)) { throw new IllegalStateException("Wrong user"); super.deleteeverything(); interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
46 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { methodinterceptor.intercept(this, Service.class.getDeclaredMethod("deleteEverything"), new Object[0], new $MethodProxy()); class $MethodProxy implements MethodProxy { // inner class semantics, can call super interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
47 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { methodinterceptor.intercept(this, Service.class.getDeclaredMethod("deleteEverything"), new Object[0], new $MethodProxy()); class $MethodProxy implements MethodProxy { // inner class semantics, can call super interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
48 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { methodinterceptor.intercept(this, Service.class.getDeclaredMethod("deleteEverything"), new Object[0], new $MethodProxy()); class $MethodProxy implements MethodProxy { // inner class semantics, can call super interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
49 ASM / BCEL Javassist cglib Byte Buddy generic delegation class SecuredService extends Service void deleteeverything() { methodinterceptor.intercept(this, Service.class.getDeclaredMethod("deleteEverything"), new Object[0], new $MethodProxy()); class $MethodProxy implements MethodProxy { // inner class semantics, can call super interface MethodInterceptor { Object intercept(object object, Method method, Object[] arguments, MethodProxy proxy) throws Throwable
50 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
51 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
52 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
53 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
54 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
55 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
56 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
57 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(value("Hello World!")).make().load(getClass().getClassLoader()).getLoaded(); assertthat(dynamictype.newinstance().tostring(), is("hello World!"));
58 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept() { return "Hello World";
59 ASM / BCEL Javassist cglib Byte Buddy Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept() { return "Hello World";
60 ASM / BCEL Javassist cglib Byte Buddy identifies best match Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept() { return "Hello World";
61 ASM / BCEL Javassist cglib Byte Buddy provides arguments Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept(@origin Method m) { return "Hello World from " + m.getname();
62 ASM / BCEL Javassist cglib Byte Buddy provides arguments Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept(@origin Method m) { return "Hello World from " + m.getname();
63 ASM / BCEL Javassist cglib Byte Buddy provides arguments Class<?> dynamictype = new ByteBuddy().subclass(Object.class).method(named("toString")).intercept(to(MyInterceptor.class)).make().load(getClass().getClassLoader()).getLoaded(); class MyInterceptor { static String intercept(@origin Method m) { return "Hello World from " + m.getname(); Annotations that are not visible to a class loader are ignored at runtime. Thus, Byte Buddy s classes can be used without Byte Buddy on the class path.
64 ASM / BCEL Javassist cglib Byte Method Class<?> String Provides caller Runnable Runnable T Allows super method call Allows default method call Provides boxed method arguments Provides argument at the given index Provides caller instance Provides super method proxy
65 ASM / BCEL Javassist cglib Byte Buddy class Foo { String bar() { return "bar"; Foo foo = new Foo(); new ByteBuddy().redefine(Foo.class).method(named("bar")).intercept(value("Hello World!")).make().load(Foo.class.getClassLoader(), ClassReloadingStrategy.installedAgent()); assertthat(foo.bar(), is("hello World!"));
66 ASM / BCEL Javassist cglib Byte Buddy class Foo { String bar() { return "bar"; Foo foo = new Foo(); new ByteBuddy().redefine(Foo.class).method(named("bar")).intercept(value("Hello World!")).make().load(Foo.class.getClassLoader(), ClassReloadingStrategy.installedAgent()); assertthat(foo.bar(), is("hello World!"));
67 ASM / BCEL Javassist cglib Byte Buddy class Foo { String bar() { return "bar"; Foo foo = new Foo(); new ByteBuddy().redefine(Foo.class).method(named("bar")).intercept(value("Hello World!")).make().load(Foo.class.getClassLoader(), ClassReloadingStrategy.installedAgent()); assertthat(foo.bar(), is("hello World!"));
68 ASM / BCEL Javassist cglib Byte Buddy class Foo { String bar() { return "bar"; Foo foo = new Foo(); new ByteBuddy().redefine(Foo.class).method(named("bar")).intercept(value("Hello World!")).make().load(Foo.class.getClassLoader(), ClassReloadingStrategy.installedAgent()); assertthat(foo.bar(), is("hello World!")); The instrumentation API does not allow introduction of new methods. This might change with JEP-159: Enhanced Class Redefiniton.
69 Byte Buddy: Java agents class Foo { String bar() { return "bar"; assertthat(new Foo().bar(), is("hello World!"));
70 Byte Buddy: Java agents class Foo { String bar() { return "bar"; assertthat(new Foo().bar(), is("hello World!")); public static void premain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().type(named("Foo")).transform( (builder, type, classloader) -> builder.method(named("bar")).intercept(value("hello World!")); ).installon(instrumentation);
71 Byte Buddy: Java agents class Foo { String bar() { return "bar"; assertthat(new Foo().bar(), is("hello World!")); public static void premain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().type(named("Foo")).transform( (builder, type, classloader) -> builder.method(named("bar")).intercept(value("hello World!")); ).installon(instrumentation);
72 Byte Buddy: Java agents class Foo { String bar() { return "bar"; assertthat(new Foo().bar(), is("hello World!")); public static void premain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().type(named("Foo")).transform( (builder, type, classloader) -> builder.method(named("bar")).intercept(value("hello World!")); ).installon(instrumentation);
73 Byte Buddy: Java agents class Foo { String bar() { return "bar"; assertthat(new Foo().bar(), is("hello World!")); public static void premain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().type(named("Foo")).transform( (builder, type, classloader) -> builder.method(named("bar")).intercept(value("hello World!")); ).installon(instrumentation);
74 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration);
75 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { return "bar";
76 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { return "bar";
77 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { long $start = System.nanoTime(); return "bar";
78 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { long $start = System.nanoTime(); return "bar";
79 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { long $start = System.nanoTime(); String $result = "bar"; return $result;
80 Byte Buddy: adding code to a method using advice class TimerAdvice static long enter() { return static void exit(@enter long String method) { long duration = System.nanoTime() - start; System.out.println(method + " took " + duration); class Foo { String bar() { long $start = System.nanoTime(); String $result = "bar"; long $duration = System.nanoTime() $start; System.out.println("Foo.bar()" + " took " + $duration); return $result;
81 Byte Buddy: Java runtime agents class Foo { String bar() { return "bar"; System.out.println(new Foo().bar()); public static void agentmain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().with(RedefinitionStrategy.RETRANSFORMATION).disableClassFormatChanges().type(named("Foo")).transform( (builder, type, classloader) -> builder.visit(advice.to(timeradvice.class).on(named("bar"))); ).installon(instrumentation);
82 Byte Buddy: Java runtime agents class Foo { String bar() { return "bar"; System.out.println(new Foo().bar()); public static void agentmain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().with(RedefinitionStrategy.RETRANSFORMATION).disableClassFormatChanges().type(named("Foo")).transform( (builder, type, classloader) -> builder.visit(advice.to(timeradvice.class).on(named("bar"))); ).installon(instrumentation);
83 Byte Buddy: Java runtime agents class Foo { String bar() { return "bar"; System.out.println(new Foo().bar()); // bar // Foo.bar() took 1630 public static void agentmain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().with(RedefinitionStrategy.RETRANSFORMATION).disableClassFormatChanges().type(named("Foo")).transform( (builder, type, classloader) -> builder.visit(advice.to(timeradvice.class).on(named("bar"))); ).installon(instrumentation);
84 Byte Buddy: Java runtime agents class Foo { String bar() { return "bar"; System.out.println(new Foo().bar()); // bar // Foo.bar() took 1630 public static void agentmain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().with(RedefinitionStrategy.RETRANSFORMATION).disableClassFormatChanges().type(named("Foo")).transform( (builder, type, classloader) -> builder.visit(advice.to(timeradvice.class).on(named("bar"))); ).installon(instrumentation);
85 Byte Buddy: Java runtime agents class Foo { String bar() { return "bar"; System.out.println(new Foo().bar()); // bar // Foo.bar() took 1630 public static void agentmain(string arguments, Instrumentation instrumentation) { new AgentBuilder.Default().with(RedefinitionStrategy.RETRANSFORMATION).disableClassFormatChanges().type(named("Foo")).transform( (builder, type, classloader) -> builder.visit(advice.to(timeradvice.class).on(named("bar"))); ).installon(instrumentation);
86 Build-time instrumentation: API public class SimplePlugin implements Plugin public boolean matches(typedescription target) { return public DynamicType.Builder<?> apply( DynamicType.Builder<?> builder, TypeDescription typedescription) { return builder.method(named("bar")).intercept(value("hello World!"));
87 Build-time instrumentation: API public class SimplePlugin implements Plugin public boolean matches(typedescription target) { return public DynamicType.Builder<?> apply( DynamicType.Builder<?> builder, TypeDescription typedescription) { return builder.method(named("bar")).intercept(value("hello World!"));
88 Build-time instrumentation: API public class SimplePlugin implements Plugin public boolean matches(typedescription target) { return public DynamicType.Builder<?> apply( DynamicType.Builder<?> builder, TypeDescription typedescription) { return builder.method(named("bar")).intercept(value("hello World!"));
89 Build-time instrumentation: API public class SimplePlugin implements Plugin public boolean matches(typedescription target) { return public DynamicType.Builder<?> apply( DynamicType.Builder<?> builder, TypeDescription typedescription) { return builder.method(named("bar")).intercept(value("hello World!"));
90 Build-time instrumentation: API public class SimplePlugin implements Plugin public boolean matches(typedescription target) { return public DynamicType.Builder<?> apply( DynamicType.Builder<?> builder, TypeDescription typedescription) { return builder.method(named("bar")).intercept(value("hello World!")); Build plugins can be applied as Java agent. Adapters allow build to agent transformation. (Agent APIs are more specific.)
91 Build-time instrumentation with Maven. <plugin> <groupid>net.bytebuddy</groupid> <artifactid>byte-buddy-maven-plugin</artifactid> <executions> <execution> <goals> <goal>transform</goal> </goals> </execution> </executions> <configuration> <transformations> <transformation> <plugin>pkg.simpleplugin</plugin> </transformation> </transformations> </configuration> </plugin>
92 Build-time instrumentation with Maven. <plugin> <groupid>net.bytebuddy</groupid> <artifactid>byte-buddy-maven-plugin</artifactid> <executions> <execution> <goals> <goal>transform</goal> </goals> </execution> </executions> <configuration> <transformations> <transformation> <plugin>pkg.simpleplugin</plugin> </transformation> </transformations> </configuration> </plugin>
93 Build-time instrumentation with Maven. <plugin> <groupid>net.bytebuddy</groupid> <artifactid>byte-buddy-maven-plugin</artifactid> <executions> <execution> <goals> <goal>transform</goal> </goals> </execution> </executions> <configuration> <transformations> <transformation> <plugin>pkg.simpleplugin</plugin> </transformation> </transformations> </configuration> </plugin>
94 Build-time instrumentation with Maven. <plugin> <groupid>net.bytebuddy</groupid> <artifactid>byte-buddy-maven-plugin</artifactid> <executions> <execution> <goals> <goal>transform</goal> </goals> </execution> </executions> <configuration> <transformations> <transformation> <plugin>pkg.simpleplugin</plugin> <artifactid>foo</artifactid> </transformation> </transformations> </configuration> </plugin>
95 Build-time instrumentation with Gradle. buildscript { repositories { jcenter() dependencies { classpath "net.bytebuddy:byte-buddy-gradle-plugin:+" apply plugin: "net.bytebuddy.byte-buddy" configurations { simpleplugin dependencies { simpleplugin "bar:foo:1.0" bytebuddy { transformation { plugin = "pkg.simpleplugin" classpath = configurations.simpleplugin
96 Build-time instrumentation with Gradle. buildscript { repositories { jcenter() dependencies { classpath "net.bytebuddy:byte-buddy-gradle-plugin:+" apply plugin: "net.bytebuddy.byte-buddy" configurations { simpleplugin dependencies { simpleplugin "bar:foo:1.0" bytebuddy { transformation { plugin = "pkg.simpleplugin" classpath = configurations.simpleplugin
97 Build-time instrumentation with Gradle. buildscript { repositories { jcenter() dependencies { classpath "net.bytebuddy:byte-buddy-gradle-plugin:+" apply plugin: "net.bytebuddy.byte-buddy" configurations { simpleplugin dependencies { simpleplugin "bar:foo:1.0" bytebuddy { transformation { plugin = "pkg.simpleplugin" classpath = configurations.simpleplugin
98 Build-time instrumentation with Gradle. buildscript { repositories { jcenter() dependencies { classpath "net.bytebuddy:byte-buddy-gradle-plugin:+" apply plugin: "net.bytebuddy.byte-buddy" configurations { simpleplugin dependencies { simpleplugin "bar:foo:1.0" bytebuddy { transformation { plugin = "pkg.simpleplugin" classpath = configurations.simpleplugin
99 Reality check: Reinvent Java? Many applications are built around a central infrastructure. A lot of code does not solve domain problems but bridges between domain and infrastructure.
100 Reality check: Reinvent Java? Many applications are built around a central infrastructure. A lot of code does not solve domain problems but bridges between domain and infrastructure. Java agents allow to add a decentralized infrastructure at runtime. In the source code, the infrastructure is only declared.
101 Reality check: Reinvent Java? Many applications are built around a central infrastructure. A lot of code does not solve domain problems but bridges between domain and infrastructure. Java agents allow to add a decentralized infrastructure at runtime. In the source code, the infrastructure is only declared. Plain old Java applications (POJAs) Working with POJOs reduces complexity. Reducing infrastructure code as a goal
102 Android makes things more complicated.
103 Android makes things more complicated. Java virtual machine [stack, JIT]
104 Android makes things more complicated. Java virtual machine [stack, JIT] Dalvik virtual machine [register, JIT]
105 Android makes things more complicated. Java virtual machine [stack, JIT] Dalvik virtual machine [register, JIT] Android runtime [register, AOT]
![[register, JIT] Android runtime [register, AOT] Solution: Embed](/docs-images/73/68269096/images/106-2.jpg "the Android SDK s dex compiler (Apache 2.0 license).")
106 Android makes things more complicated. Java virtual machine [stack, JIT] Dalvik virtual machine [register, JIT] Android runtime [register, AOT] Solution: Embed the Android SDK s dex compiler (Apache 2.0 license). Unfortunately, only subclass instrumentation possible.
107 Performance: library comparison baseline Byte Buddy cglib Javassist Java proxy (1) (2a) (2b) (3a) (3b) n/a n/a Results are measured in nanoseconds (rounded). All benchmarks run with JMH, source code: (1) Extending the Object class without any methods but with a default constructor (2a) Implementing an interface with 18 methods, method stubs (2b) Executing a method of this interface (3a) Extending a class with 18 methods, super method invocation (3b) Executing a method of this class
108 Performance: library comparison baseline Byte Buddy cglib Javassist Java proxy (1) (2a) (2b) (3a) (3b) n/a n/a Results are measured in nanoseconds (rounded). All benchmarks run with JMH, source code: (1) Extending the Object class without any methods but with a default constructor (2a) Implementing an interface with 18 methods, method stubs (2b) Executing a method of this interface (3a) Extending a class with 18 methods, super method invocation (3b) Executing a method of this class
109 Performance: library comparison baseline Byte Buddy cglib Javassist Java proxy (1) (2a) (2b) (3a) (3b) n/a n/a Results are measured in nanoseconds (rounded). All benchmarks run with JMH, source code: (1) Extending the Object class without any methods but with a default constructor (2a) Implementing an interface with 18 methods, method stubs (2b) Executing a method of this interface (3a) Extending a class with 18 methods, super method invocation (3b) Executing a method of this class
110 Performance: delegation vs. advice foo() bar() qux()
111 Performance: delegation vs. advice foo() bar() intercept() qux()
112 Performance: delegation vs. advice foo() foo() bar() bar() intercept() qux() qux()
113 Performance: delegation vs. advice foo() foo() bar() I bar() O intercept() qux() qux()
114 Performance: delegation vs. advice foo() foo() -XX:MaxInlineSize=35 (auto-reduced) -XX:FreqInlineSize=325 -XX:InlineSmallCode=2000 -XX:MaxInlineLevel=9 bar() I bar() O -XX:InlineSynchronizedMethods=true -XX:ReservedCodeCacheSize=48M -XX:+PrintCodeCache -XX:+PrintCodeCacheOnCompilation intercept() qux() qux()
115 Java 9: instrumentation meets modules foo() [module A] bar() [module A] instrumentation.addreads(modulea, moduleb); qux() [module A]
116 Java 9: instrumentation meets modules foo() [module A] bar() [module A] instrumentation.addreads(modulea, moduleb); intercept() [module B] qux() [module A]
117 Java 9: instrumentation meets modules foo() [module A] Module modulea = findmodule("a"), moduleb = findmodule("b"); modulea.addreads(moduleb); bar() [module A] instrumentation.addreads(modulea, moduleb); intercept() [module B] qux() [module A]
118 Loading and leaking runtime classes boot extension system
119 Loading and leaking runtime classes boot extension system Foo
120 Loading and leaking runtime classes boot extension system Bar [inject] Foo
121 Loading and leaking runtime classes boot extension system wrapper Bar [inject] Foo Bar [wrapper]
122 Loading and leaking runtime classes boot extension system wrapper Bar [inject] Foo Bar [wrapper] public class Foo { /* package-private */ String bar() { return "foo"; public class Bar extends Foo /* package-private */ String bar() { return "bar";
123 Loading and leaking runtime classes boot extension system wrapper Bar [inject] Foo Bar [wrapper] public class Foo { /* package-private */ String bar() { return "foo"; public class Bar extends Foo /* package-private */ String bar() { return "bar";
124 Loading and leaking runtime classes boot extension system wrapper Bar [inject] Foo Bar [wrapper] public class Foo { /* package-private */ String bar() { return "foo"; public class Bar extends Foo /* package-private */ String bar() { return "bar";
125 Caching runtime classes Foo Foo$Proxy
126 Caching runtime classes Foo Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies;
127 Caching runtime classes Foo via CL Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies;
128 Caching runtime classes Foo via CL Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies; Map<Class<?>, Class<?>> Value references key strongly (parent class). Requires active life-cycle management. When injecting into the source class loader, this is the only meaningful solution.
129 Caching runtime classes Foo via CL Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies; Map<Class<?>, Class<?>> Value references key strongly (parent class). Requires active life-cycle management. When injecting into the source class loader, this is the only meaningful solution. WeakHashMap<Class<?>, WeakReference<Class<?>>> Proxy class is collected when there is no instance available.
130 Caching runtime classes Foo via CL Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies; Map<Class<?>, Class<?>> Value references key strongly (parent class). Requires active life-cycle management. When injecting into the source class loader, this is the only meaningful solution. WeakHashMap<Class<?>, WeakReference<Class<?>>> Proxy class is collected when there is no instance available. WeakHashMap<Class<?>, SoftReference<Class<?>>> Proxy class is collected when the heap is filled and there is no instance available.
131 Caching runtime classes Foo via CL Foo$Proxy WeakHashMap<Class<?>, Class<?>> proxies; Map<Class<?>, Class<?>> Value references key strongly (parent class). Requires active life-cycle management. When injecting into the source class loader, this is the only meaningful solution. WeakHashMap<Class<?>, WeakReference<Class<?>>> Proxy class is collected when there is no instance available. WeakHashMap<Class<?>, SoftReference<Class<?>>> Proxy class is collected when the heap is filled and there is no instance available. The only proper solution would be ephemerons which are not available in the JVM. Discussed in January 2016 / OpenJDK mailing list (core-libs-dev).
132 Dealing with bridge methods class Foo<T> { void bar(t arg) { /* do something */ class Bar<S extends Number> extends Foo<S> void bar(s arg) { /* do something */
133 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg);
134 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg);
135 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg); class Bar$Proxy extends Bar void bar(number arg) { void bar(object arg) { super.bar(arg);
136 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg); class Bar$Proxy extends Bar void bar(number arg) { void bar(object arg) { super.bar(arg);
137 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg); class Bar$Proxy extends Bar void bar(number arg) { void bar(object arg) { super.bar(arg);
138 Dealing with bridge methods class Foo { void bar(object arg) { /* do something */ class Bar extends Foo void bar(number arg) { /* do something */ /* bridge */ void bar(object arg) { this.bar((number) arg); class Bar$Proxy extends Bar void bar(number arg) { void bar(object arg) { super.bar(arg);
139 Dealing with bridge methods: visibility bridges class Foo { public void bar() { /* do something */ public class Bar extends Foo {
140 Dealing with bridge methods: visibility bridges class Foo { public void bar() { /* do something */ public class Bar extends Foo { /* bridge */ public void bar() { super.bar();
141 Dealing with bridge methods: visibility bridges class Foo { public void bar() { /* do something */ public class Bar extends Foo { /* bridge */ public void bar() { super.bar();
142 Dealing with bridge methods: visibility bridges class Foo { public void bar() { /* do something */ public class Bar extends Foo { /* bridge */ public void bar() { super.bar(); class Qux { public final void bar() { /* do something */ public class Baz extends Qux {
143 Dealing with bridge methods: visibility bridges class Foo { public void bar() { /* do something */ public class Bar extends Foo { /* bridge */ public void bar() { super.bar(); class Qux { public final void bar() { /* do something */ public class Baz extends Qux { new Baz().bar(); // works Baz.class.getMethod("bar").invoke(new Baz()); // access error
144 Generic runtime types and dealing with meta Foo { interface Bar<T> void foo(@foo this, T arg);
145 Generic runtime types and dealing with meta Foo { interface Bar<T> void foo(@foo this, T arg); new ByteBuddy().subclass(parameterizedType(Bar.class, String.class).build()).method(named("foo")).intercept(value("bar")).attribute(ForInstrumentedMethod.INCLUDING_RECEIVER).make();
146 Generic runtime types and dealing with meta Foo { interface Bar<T> void foo(@foo this, T arg); new ByteBuddy().subclass(parameterizedType(Bar.class, String.class).build()).method(named("foo")).intercept(value("bar")).attribute(ForInstrumentedMethod.INCLUDING_RECEIVER).make();
147 Generic runtime types and dealing with meta Foo { interface Bar<T> void foo(@foo this, T arg); new ByteBuddy().subclass(parameterizedType(Bar.class, String.class).build()).method(named("foo")).intercept(value("bar")).attribute(ForInstrumentedMethod.INCLUDING_RECEIVER).make();
148 Generic runtime types and dealing with meta Foo { interface Bar<T> void foo(@foo this, T arg); new ByteBuddy().subclass(parameterizedType(Bar.class, String.class).build()).method(named("foo")).intercept(value("bar")).attribute(ForInstrumentedMethod.INCLUDING_RECEIVER).make(); Byte Buddy handles meta data and generic types transparently. Not only important for build-time instrumentation but also for meta data APIs.
149 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg);
150 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $MethodProxy implements MethodProxy public Object invokesuper(object self, Method method, Object[] arguments) { if (method.equals($bar)) { ((Foo) self).bar((integer) arguments[0]); return null; else if (method.equals($qux)) { return ((Foo) self).qux((string) arguments[0]); else { throw new IllegalStateException();
151 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $MethodProxy implements MethodProxy public Object invokesuper(object self, Method method, Object[] arguments) { if (method.equals($bar)) { ((Foo) self).bar((integer) arguments[0]); return null; else if (method.equals($qux)) { return ((Foo) self).qux((string) arguments[0]); else { throw new IllegalStateException();
152 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $MethodProxy implements MethodProxy public Object invokesuper(object self, Method method, Object[] arguments) { if (method.equals($bar)) { ((Foo) self).bar((integer) arguments[0]); return null; else if (method.equals($qux)) { return ((Foo) self).qux((string) arguments[0]); else { throw new IllegalStateException();
153 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $MethodProxy implements MethodProxy public Object invokesuper(object self, Method method, Object[] arguments) { if (method.equals($bar)) { ((Foo) self).bar((integer) arguments[0]); return null; else if (method.equals($qux)) { return ((Foo) self).qux((string) arguments[0]); else { throw new IllegalStateException();
154 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg);
155 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $BarMethodProxy implements Runnable { final Foo self; final int arg; // constructor public void run() { self.bar(arg);
156 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $BarMethodProxy implements Runnable { final Foo self; final int arg; // constructor public void run() { self.bar(arg);
157 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $BarMethodProxy implements Runnable { final Foo self; final int arg; // constructor public void run() { self.bar(arg);
158 Super method proxies: cglib interface Foo { void bar(int arg); String qux(string arg); class $BarMethodProxy implements Runnable { final Foo self; final int arg; // constructor public void run() { self.bar(arg); class $QuxMethodProxy implements Callable<String> { final Foo self; final String arg; // constructor public String call() { return self.bar(arg);
159 Problems caused by optional types class SomeFramework { void doframeworkstuff() { if (isfancypluginavailable()) { init(new OptionalPluginType()); /* do work */ private void init(optionalplugintype plugin) { /* do work */
160 Problems caused by optional types class SomeFramework { void doframeworkstuff() { if (isfancypluginavailable()) { init(new OptionalPluginType()); /* do work */ private void init(optionalplugintype plugin) { /* do work */
161 Problems caused by optional types class SomeFramework { void doframeworkstuff() { if (isfancypluginavailable()) { init(new OptionalPluginType()); /* do work */ private void init(optionalplugintype plugin) { /* do work */
162 Problems caused by optional types class SomeFramework { void doframeworkstuff() { if (isfancypluginavailable()) { init(new OptionalPluginType()); /* do work */ private void init(optionalplugintype plugin) { /* do work */ // causes NoClassDefFoundError SomeFramework.class.getMethods();
163 Not requiring loaded types: an reflection API alternative When a class file transformer is applied, a class is not yet loaded and it is therefore not possible to access loaded types. To provide an API for matchers and transformers, Byte Buddy offers an abstraction to the Java reflection API: interface TypeDescription interface MethodDescription interface FieldDescription interface AnnotationDescription Any reference of such a description is resolved lazily. This also allows working with optional types. The Byte Buddy agent builder offers an automatic fallback as using loaded types is more performant.
164
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