Why do we need jvm

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Thanks for your answer! I just have a few more questions to ask regarding the points you made. You mentioned that Bytecode is smaller than source code, but when I checked one of my practice programs that I made before, I found that, actually, the source code is smaller than bytecode respectively 1, bytes vs. How could this happen? Also, you pointed out that Bytecode is harder to reverse-engineer. In what way is this accomplished? Like in terms of reverse-compiling?

Lemon: Small classes, particularly ones without JavaDoc or other comments, and most particularly ones compiled with debugging information, can go the other way.

Re reverse engineering: A search will turn up all kinds of tools to turn bytecode back into source code. You lose local variable names, but The java compiler converts the java source to bytecode. The JVM only executes bytecode. JVMs on different operating systems can run the same bytecode. Other languages like Scala can also be compiled to bytecode and run on a JVM. The compilation improves execution efficiency and security.

Dragonthoughts Dragonthoughts 2, 8 8 gold badges 22 22 silver badges 25 25 bronze badges. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming This is just in time compiling.

It is one of the main reason why Java is comparatively slow. It interprets part of the Byte Code that has similar functionality at the same time. Programming languages are classified as. A compiler is a program which converts a program from one level of language to another.

The java compiler converts high-level java code into bytecode which is also a type of machine code. An interpreter is a program which converts a program at one level to another programming language at the same level.

In Java, the Just In Time Code generator converts the bytecode into the native machine code which are at the same programming levels. Skip to content. What is JVM? Report a Bug. Previous Prev. Next Continue. Home Testing Expand child menu Expand. SAP Expand child menu Expand. Web Expand child menu Expand. Must Learn Expand child menu Expand. Big Data Expand child menu Expand.