Java Basics

[Kunal Lakhani]

As we say , after compilation of java code, bytecode is generated.

In this context, what is JVM and bytecode?

[fred rosenberger]

Java bytecode is a special language that the Java Virtual Machine (JVM) understands. The JVM is basically a program that knows how to read bytecode and talk to a specific operating system/platform. So, there is a JVM for windows XP, a JVM for linux, a JVM for Mac OS.10, etc.

You can give the exact same .class file (which is bytecode) to any JVM, and it will interpret it for the machine where it runs.

this is vastly different from something like C. You'd need to compile your C code for each platform, and make sure you sent the correct (set of) file(s) for that OS. That often lead to maintenance nightmares.

[Kunal Lakhani]

we say java is a secure language. Is this bytecode concept related to java security?

[fred rosenberger]

no.

[Kunal Lakhani]

So, what makes java a secure language?

[Henry Wong]

Kunal Lakhani wrote:So, what makes java a secure language?

No easy answer. Java is secure due to many components; from the byte code verifier, the class loaders, the security manager, and how many of the classes are designed and behave (immutability, etc.).

Henry

[Jesper de Jong]

Kunal Lakhani wrote:As we say , after compilation of java code, bytecode is generated.

In this context, what is JVM and bytecode?

The following page in Oracle's Java Tutorials explains these basic principles: About the Java Technology.