Are default field values assigned by the compiler or the JVM?

Question

I have one question: in java we declare int,long,double etc.,(primitive data) or non primitive (object data), not initialized with default values, but at run time

Answer 1

There are three different types of declared variables in Java. They are instance, class and local variables.

Instance Variables

Instance variables are the non-static fields of your class, often referred to simply as fields.

• Primitive numeric fields initialize to 0. This includes byte, short, int, long, float and double.

• booleans initialize to false .

• chars initialize to the null character \u0000.

• Reference types initialize to null.

Class Variables

A class variable is a field within a class declared as static, often referred to as a static variable or static field. It is also same initialize as instance variable.

Local Variables

A local variable is a variable defined within a method, which includes any method parameters. Local variables must be initialized before use. They do not have a default value.

Initialization process is done by JVM when method is create.