Link to download java:

Lecture 1:

Lecture 3:

How Java program run.

“” compiler converts it to “hello.class”
the byte code or the “.class” file generated by java compiler cannot be understood by any operating system which doesn’t have java virtual environment installed in it.

we need to have JVM in order to run any java’s “.class” file.
JVM has Just-in-time Compiler which act as both Interpreter and compiler.
It compiles and executes codes line by line and by the time the code is being executed it compile and store the next line for execution to the operating system.
JVM is operating system dependent.

Upon installing java two things are installed, Java JDK and Java JRE. JDK is needed to develop java programs, and JRE for running java programs.
* JDK:- Java Developer Kit has tools needed to develop java programs. javac.exe, java.exe, etc.
* JRE:- Java Runtime Environment has JVM and java packages/ java library.


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