what are Local Variables ?

Variables declared within a method. That means the variable is not just initialized within the method, but also declared within the method. As local variables starts its life inside the method, it's also destroyed when the method has completed. Local variables are always on stack and not on heap.


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What is Array?

Arrays are objects that store multiple variables of the same type or variables that are all subclasses of the same type.

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What are Constructors?

A constructor is always invoked when a new object is created. Every class has atleast one constructor. Constructor must have the same name as the class name. Constructors don't have a return type. The default constructor is a no-arg constructor.


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How to request for Garbage Collection?

You can request for garbage collection with System.gc();


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What is an Exception?

An abnormal condition that occurs during normal program flow.

There are two types of exception:
1. checked
2. unchecked.

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Difference between String and StringBuffer ?

String objects are immutable and String reference variables are not.
StringBuffer objects are mutable.


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What is a Thread?

A Thread is a line of execution. It is an instance of class java.lang.Thread.
There is one thread per call stack.

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