MODULE 1 JAVA PLATFORMS. Identifying Java Technology Product Groups

Transcription

1 MODULE 1 JAVA PLATFORMS Identifying Java Technology Product Groups

2 Java SE Platform Versions Year Developer Version (JDK) Platform Java s Place in the World > Over 9 million developers saying they spend at least some of their time developing in Java, according to a recent study. > That s out of a world population of about 14 million developers

3 Java Desktops > 1.1 billion desktops run Java (Nielsen Online, Gartner 2010). > 930 million JRE downloads a year (August ): The JRE (Java runtime environment) is used by end users. > 9.5 million JDK downloads a year (August ): The JDK (Java Development Kit) is used by Java developers Java TV and Card > 100% of Blu ray players run Java. > 71.2 million people connect to the web on Java powered devices (InStat 2010). > 1.4 billion Java Cards are manufactured every year (InStat 2010).

4 > Once upon a time The Story of Java Java SE > Is used to develop applets that run within web browsers and applications that run on desktop computers

5 Java EE > Is used to create large enterprise, server side, and clientside distributed applications Java ME > Is used to create applications for resource constrained consumer devices

6 Java Card > Java Card is typically used in the following areas (and many more): Identity Security Transactions Mobile phone SIMs Java SE and Java ME Convergence > Java 8 is an evolutionary step > We have updates in the language the Platform the APIs APIs Language Java SE 8 Java SE 8 Java ME 8 Java ME 8

7 JVM Languages jgo ANTLR Gosu Fortress Jaskell Nice ABCL X10 Jacl Erjang BeanShell Fantom Dynamic Languages > Dynamic Languages are hot today because They are easy to use They have no explicit compile stage They have good code readability Allow short development time for small projects Performance is good enough

8 invokedynamic > The first new bytecode since 1996 > More than new type of call > Breaks the constraints of Java call/linkage > Can implement calls that act like function pointers > More general: can implement custom data access It s not just invokedynamic! The JVM is evolving to become the multi language runtime

9 The Platform Architecture 1/4 Java EE Application Java SE Application JVM (HotSpot, JRockit, Zing, J9, ) Java EE AS (GF, JBoss, WLS, WSphere, ) JVM (HotSpot, JRockit, Zing, J9, ) OS (Windows, Linux, Solaris, ) OS (Windows, Linux, Solaris, ) HW (CPU,GPU,Memory,HD, ) HW (CPU,GPU,Memory,HD, ) The Platform Architecture 2/4 Java SE App. Java SE App. JRockit VE Virtual Edition WebSphere HE Hypervisor Edition JVM JVM Java SE App Java SE App OS OS JVM JVM... VM #1... VM #n VM #1 VM #n Virtualization (Baremetal) HW (CPU,GPU,Memory,HD, ) Virtualization (Baremetal) HW (CPU,GPU,Memory,HD, )

10 The Platform Architecture 3/4 Java EE App Java EE App Java EE AS JVM... Java EE AS JVM... VM #1 VM #n Virtualization (Baremetal) HW (CPU,GPU,Memory,HD, ) The Platform Architecture 4/4

11 What is Docker? > Open Source Project and Company > Used to create containers for software applications > Package Once Deploy Anywhere (PODA) Advantages > Faster deployments > Isolation > Portability it works on my machine > Snapshotting > Security sandbox > Limit resource usage > Simplified dependency > Sharing

12 > Written in Go Underlying Technology > Uses several Linux features Namespaces to provide isolation Control groups to share/limit hardware resources Union File System makes it light and fast libcontainer defines container format > Natively supported in Linux Windows 10 Windows Server 2016 Is it only Linux?

13 Virtual Machines Docker

14 Kubernetes > Open source orchestration system for Docker containers > Provide declarative primitives for the desired state Self healing Auto restarting Schedule across hosts Replicating Setting Up the Java Development Environment > It is easy to set up your Java development environment. 1.Download and install the Java Development Kit (JDK) from oracle.com/java. 2.Set your PATH to the installed JDK. 3.Compile and run a Java application by using the command line.

15 Downloading and Installing the JDK 1. Go to oracle.com/java. Downloading and Installing the JDK 2. Select the Java Platform, Standard Edition (Java SE) link. 3. Download the version for your platform. 4. Follow the installation instructions. 5. Set your Java PATH. 6. Compile and run a sample Java application.

16 g Kit p HotSpot JVM: Architecture

17 HotSpot JVM: Architecture Class Files Class Loader Subsystem Method Area Heap Java Threads Program Counter Registers Native Internal Threads Runtime Data Areas Execution Engine JIT Compiler Garbage Collector Native Method Interface Native Method Libraries Java Program and Compiled Class File

18 A Java Class File A Java Class File (Cont d)

19 Key HotSpot JVM Components Class Files Class Loader Subsystem Method Area Heap Java Threads Program Counter Registers Native Internal Threads Runtime Data Areas Execution Engine JIT Compiler Garbage Collector Native Method Interface Native Method Libraries JVM > HotSpot, JRockit, Zing, Zulu, J9, > 32 bit JVM vs 64 bit JVM > Client VM vs Server VM > Mixed Mode vs Compiled Mode vs Interpreted Mode > Sharing vs Non Sharing

20 > java version JVM java version "1.8.0_25" Java(TM) SE Runtime Environment (build 1.8.0_25 b18) Java HotSpot(TM) 64 Bit Server VM (build b02, mixed mode) > java version java version "1.7.0_51" Java(TM) SE Runtime Environment (build 1.7.0_51 b13) Java HotSpot(TM) Client VM (build b03, mixed mode, sharing) JVM Options > XX:+UnlockDiagnosticVMOptions > XX:+UnlockExperimentalVMOptions > XX:+AggressiveOpts > XX:++PrintFlagsFinal

21 JVM Options uintx AdaptiveSizeDecrementScaleFactor = 4 {product} uintx AdaptiveSizeMajorGCDecayTimeScale = 10 {product} uintx AdaptiveSizePausePolicy = 0 {product} uintx AdaptiveSizePolicyCollectionCostMargin = 50 {product} uintx AdaptiveSizePolicyInitializingSteps = 20 {product} uintx AdaptiveSizePolicyOutputInterval = 0 {product} uintx AdaptiveSizePolicyWeight = 10 {product} uintx AdaptiveSizeThroughPutPolicy = 0 {product} uintx AdaptiveTimeWeight = 25 {product} JIT Compilation -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompilation -XX:+PrintAssembly -XX:+LogCompilation -XX:LogFile=<path to file>

22 Non Standard Options > $ java X List all non standard options. > Xint Runs the application in interpreted only mode. > Xbootclasspath:path Path and archive list of boot class files. > Xloggc:filename Log verbose GC events to filename. > Xms1g Set the initial size (in bytes) of the heap. > Xmx8g Specifies the max size (in bytes) of the heap. Non Standard Options > Xnoclassgc Disables class garbage collection. > Xprof Profiles the running program

23 DEBUGGING > XX:ErrorFile=file.log Save the error data to file.log. > XX:+HeapDumpOnOutOfMemory Enables heap dump when OutOfMemoryError is thrown. > XX:+PrintGC Enables printing messages during garbage collection. > XX:+TraceClassLoading Enables Trace loading of classes. > XX:+PrintClassHistogram Enables printing of a class instance histogram after a Control+C event (SIGTERM) PERFORMANCE > XX:MaxPermSize=128m (Java 7 or earlier) Sets the max perm space size (in bytes). > XX:ThreadStackSize=256k Sets Thread Stack Size (in bytes) (Same as Xss256k) > XX:+UseStringCache > Enables caching of commonly allocated strings. > XX:G1HeapRegionSize=4m > Sets the sub division size of G1 heap (in bytes). > XX:MaxGCPauseMillis=n Sets a target for the maximum GC pause time. > XX:MaxNewSize=256m Max size of new generation (in bytes).

24 PERFORMANCE > XX:+AggressiveOpts Enables the use of aggressive performance optimization features. > XX:OnError="<cmd args> Run user defined commands on fatal error