EXPLAIN KEYS AND TYPES OF KEYS IN DBMS

A variable is a container which holds the value while the Java program is executed. A variable is assigned with a data type.

Variable is name of reserved area allocated in memory. In other words, it is a name of memory location. It is a combination of "vary + able" that means its value can be changed.
Variable is a name of memory location. There are three types of variables in java: local, instance and static.
For example : int a=50;      //Here a is variable  

Types of Variables

There are three types of variables in Java:

• local variable

• instance variable

• static variable

1) Local Variable : -

A variable declared inside the body of the method is called local variable. A local variable cannot be defined with "static" keyword.

2) Instance Variable : -

A variable declared inside the class but outside the body of the method, is called instance variable. It is not declared as static. It is called instance variable because its value is instance specific and is not shared among instances.

3) Static variable : -

A variable which is declared as static is called static variable. It cannot be local.

For example to understand all types of variables in java : -

class MyClass {
static int a = 10; //static variable

int b = 20; //instance variable
int c = 30; //local variable

void method() {
}
}