Basics

Java Data Types

Java data types include int String and boolean with primitives.

Introduction to Java Data Types

Java data types are fundamental in defining the kind of data a variable can hold. They specify the size and type of values that can be stored and manipulated within a program. Java has two categories of data types: primitive and non-primitive (or reference types).

Primitive Data Types

Primitive data types are predefined by Java and named by a reserved keyword. There are eight primitive data types in Java:

byte: 8-bit integer
short: 16-bit integer
int: 32-bit integer
long: 64-bit integer
float: single-precision 32-bit IEEE 754 floating point
double: double-precision 64-bit IEEE 754 floating point
boolean: represents one bit of information, either true or false
char: 16-bit Unicode character

Non-Primitive Data Types

Non-primitive data types, also known as reference types, include classes, interfaces, and arrays. Unlike primitive types, they are not defined by Java but by the user. These types can be used to call methods to perform certain operations, while primitive types cannot.

The most commonly used non-primitive data type is String, which is a class in Java.

Default Values of Data Types

Each data type in Java has a default value. If a variable is declared but not initialized, it holds the default value for its type:

byte, short, int, long: 0
float, double: 0.0
char: '\u0000'
boolean: false
String (and other objects): null

Conclusion

Understanding Java data types is essential for efficient programming. By choosing the right data type, you can ensure optimal performance and resource usage in your Java applications. As you continue to learn, keep practicing with different data types to become more familiar with their behaviors and limitations.

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