Tuesday, October 2, 2012
Questions : 1 | What is JVM (Java Virtual Machine) ? |
Answers : 1 |
JVM stands for Java Virtual Machine. It’s an abstract
computer or virtual computer which
runs the compiled java programs. Actually JVM is a software
implementation which stands
on the top of the real hardware platform and operating system. It
provides abstraction
between the compiled java program and the hardware and operating system.
So the compiled program does not have to worry about what hardware and
operating
system he has to run in, it’s all handled by the JVM and thus attaining
portability. All Java
programs are compiled in to bytecodes. JVM can only understand and
execute Java
bytecodes. we can visualize Java bytecodes as machine language for JVM.
Java compiler
takes the .java files and compiles it to a “bytecode” file with .class
file extension. Compiler
generates one class file for one source file.
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Questions : 2 | What is JIT (Just-in-Time) Compilation ? |
Answers : 2 |
When JVM compiles the class file he does not compile
the full class file in one shot. Compilation is done on function basis or file basis. Advantage
gained from this is that heavy parsing of original source code is avoided. Depending on
need basis the compilation is done. This typ of compilation is termed as JIT or Just-in-
Time compilation.
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Questions : 3 | How do you implement inheritance in Java? |
Answers : 3 |
nheritance is implemented by using
“EXTEND” keyword.
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