What are the data types of java

Java data types: 1. Integer type; 2. Floating point type; 3. Character type; 4. Boolean type; 5. Other data types; 6. Reference types; 7. Primitive types and encapsulated classes; 8. Automatic boxing and unboxing; 9. Variable parameters; 10. Annotations; 11. Enumeration; 12. Selection of primitive types and reference types. Java is a strongly typed language, so every data has its fixed type.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Java is a strongly typed language, so each type of data has its fixed type. The following are the basic data types in Java:

1. Integer Types:

• byte: 8-bit signed integer, value range is -128 to 127.
• short: 16-bit signed integer, value range is -32768 to 32767.
• int: 32-bit signed integer, the value range is -2147483648 to 2147483647. This is the most commonly used integer type.
• long: 64-bit signed integer, the value range is -9223372036854775808 to 9223372036854775807. When the value is very large or very small, beyond the range of an int, you can use long.

2. Floating Point Types:

• float: 32-bit IEEE 754 single-precision floating point number.
• double: 64-bit IEEE 754 double-precision floating point number. This is the most commonly used floating point number type.

3. Character Types:

• char: 16-bit Unicode character.

4. Boolean Types:

• boolean: There are only two values: true and false.

5. Other data types:

• void: means no type, mainly used for the return type of the method, indicating that the method does not return any value .
• String: Represents the string type, often used to store and operate text data.
• Array Types: Can store multiple values ​​of the same data type. For example, int[] is an integer array that can store multiple integer values.

6. Reference types: These types include classes, interfaces and arrays. They store references to objects, not the objects themselves. This means that when we declare a reference variable and allocate an object to it, the variable actually stores the memory address of the object, not the object itself.

7. Primitive types and encapsulation classes: For integer, floating point, character and Boolean types, Java provides corresponding encapsulation classes, namely Integer, Float, Character and Boolean. These wrapper classes provide additional functionality such as autoboxing and unboxing, object comparison, etc.

8. Automatic boxing and unboxing: Java will automatically convert basic data types (such as int) and their encapsulation classes (such as Integer). This conversion is called loading. Boxing and unboxing. For example, when assigning an int value to an Integer object, Java automatically boxes the int value into an Integer object; conversely, when extracting a value from an Integer object, Java automatically unboxes the value.

9. Variable parameters (varargs): Starting from Java 5, methods can accept a variable number of parameters. These parameters can be declared using the varargs keyword and handled as arrays. For example, void printAll(String... args) can accept any number of String arguments.

10. Annotation: Annotations are used to add metadata to the code. They are typically used to provide compile-time or run-time information but do not affect the execution logic of the code. For example, you can use annotations to mark certain parts of the code, provide parameter information for methods, or generate documentation.

11. Enumeration (Enum): An enumeration is a special class that defines a set of constant values. Enumerations are often used to represent a set of fixed constant values, such as days of the week, months, etc.

12. Selection of primitive types and reference types: In most cases, primitive types should be used in preference to their encapsulated classes, because primitive types save more memory and have better performance . But when you need to compare a primitive type value with null or need to use autoboxing/unboxing functionality, you should use a wrapper class.

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