JIT

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Presented By: Anjali CSE/08/305 Presentation on JRE and JIT

JIT:

JIT Just-in-time compilation ( JIT ), also known as dynamic translation , is a method to improve the runtime performance of computer programs . JIT is the part of the Java Virtual Machine (JVM) that is used to speed up the execution time. JIT compiles parts of the byte code that have similar functionality at the same time, and hence reduces the amount of time needed for compilation.

Modes of runtime operation:

Modes of runtime operation Computer programs had two modes of runtime operation, either interpreted or static ( ahead-of-time ) compilation.[ citation needed ] Interpreted code is translated from a high-level language to a machine code continuously during every execution, whereas statically compiled code is translated into machine code before execution, and only requires this translation once.

Goals of Jit:

Goals of Jit A common goal of using JIT techniques is to reach or surpass the performance of static compilation, while maintaining the advantages of bytecode interpretation The deployed bytecode is portable, unlike native code. Compilers from bytecode to machine code are easier to write. JIT code generally offers far better performance than interpreters.

Benefits of Jit:

Benefits of Jit The compilation can be optimized to the targeted CPU and the operating system model where the application runs The system is able to collect statistics about how the program is actually running in the environment it is in, and it can rearrange and recompile for optimum performance. The system can do global code optimizations Bytecode system can more easily rearrange executed code for better cache utilization.

JRE:

JRE The JRE is the Java Runtime Environment. The JRE, or Java RTE , is developed by Sun Microsystems (the creator of Java) and includes the Java Virtual Machine (JVM), code libraries, and components, which are necessary to run programs written in Java. The JRE is available for multiple computer platforms, including Mac, Windows, and Unix.

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JRE (Java Runtime Environment) Who needs it? Computer users who run applets and applications written using Java technology What is it? An environment required to run applets and applications written using the Java programming language How do you get it? Distributed freely and is available from: http://java.com

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Two key deployment technologies are part of the JRE: Java Plug-in, which enables applets to run in popular browsers; and Java Web Start, which deploys standalone applications over a network. The JRE consists of the Java Virtual Machine , the Java libraries, and all other components necessary to run Java applications and applets written in java programming language .

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The JRE software provides a runtime environment in which Java If the JRE is not installed on a computer, Java programs may not be recognized by the operating system and will not run. JRE software is available as both a standalone environment and a Web browser plug-in , which allows Java applets to be run within a Web browser .

Differentiate JVM JRE JDK JIT :

Differentiate JVM JRE JDK JIT Java Virtual Machine (JVM) is an abstract computing machine. Java Runtime Environment (JRE) is an implementation of the JVM. Java Development Kit (JDK) contains JRE along with various development tools like Java libraries, Java source compilers, Java debuggers, bundling and deployment tools. JVM becomes an instance of JRE at runtime of a java program. It is widely known as a runtime interpreter. The Java virtual machine (JVM) is the cornerstone on top of which the Java technology is built upon. It is the component of the Java technology responsible for its hardware and platform independence. JVM largely helps in the abstraction of inner implementation from the programmers who make use of libraries for their programmes from JDK.

Features:

Features JRE (Java Runtime environment). It is an implementation of the Java Virtual Machine* which actually executes Java programs. Java Run Time Environment is a plug-in needed for running java programs. JRE is smaller than JDK so it needs less Disk space. JRE can be downloaded/supported freely from java.com It includes JVM , Core libraries and other additional components to run applications and applets written in Java.

Thank you:

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