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    In Java, variables are containers for storing data values, and they are classified based on scope, lifetime, and accessibility into three main types: Local, Instance, and Static variables.

    1. Local Variables These are declared inside a method, constructor, or block and are created when the method is invoked, destroyed when it ends. They must be initialized before use and have no default value.

    public class Demo {
    public static void main(String[] args) {
    int num = 10; // Local variable
    System.out.println("Local Variable: " + num);
    }
    }
    コピーしました。

    Key Points: Scope is limited to the block; cannot use access modifiers.

    2. Instance Variables Declared inside a class but outside any method, these belong to an object. Each object has its own copy, and they can have access modifiers. They get default values if not initialized.

    class Person {
    String name; // Instance variable
    int age; // Instance variable

    Person(String name, int age) {
    this.name = name;
    this.age = age;
    }
    public void display() {
    System.out.println(name + " is " + age + " years old.");
    }
    }
    public class Demo {
    public static void main(String[] args) {
    Person p1 = new Person("Alice", 25);
    p1.display();
    }
    }
    コピーしました。
    What are the different types of data types in Java?
    There are two types of data types in Java: primitive and non-primitive. A variable is the name of a reserved area allocated in memory. In other words, it is a name of the memory location. It is a combination of "vary + able" which means its value can be changed. A variable declared inside the body of the method is called local variable.
    tpointtech.com
    TutorialsPoint
    https://www.tutorialspoint.com/java/java_variable_types
    Java - Variable Types - Online Tutorials Library
  1. GeeksForGeeks
    https://www.geeksforgeeks.org › java › ty…この結果を翻訳する

    Types of Java Variables - GeeksforGeeks

    2025年10月3日 · In Java, variables are containers that store data values, such as numbers, text, or Boolean values. Java variables are categorized into different …

  2. W3School
    https://www.w3schools.com › java › java…この結果を翻訳する

    Java Variables - W3Schools

    Java Variables Variables are containers for storing data values. In Java, there are different types of variables, for example: String - stores text, such as "Hello". …

    使用例
    type variableName = value;
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  3. oracle.com
    https://docs.oracle.com › javase › specs › jls › htmlこの結果を翻訳する

    Chapter 4. Types, Values, and Variables - Oracle Help Center

      1. The Kinds of Types and Values. There are two kinds of types in the Java programming language: …
      2. Primitive Types and Values. A primitive type is predefined by the Java programming language and …
      3. Reference Types and Values. There are four kinds of reference types: class types (§8), interface …
      4. Type Variables. A type variable is an unqualified identifier used as a type in class, interface, method, …
      5. Parameterized Types. A generic class or interface declaration C (§8.1.2, §9.1.2) with one or more …
      docs.oracle.com で完全なリストを表示
  4. TutorialsPoint
    https://www.tutorialspoint.com › java › java_variable_typesこの結果を翻訳する

    Java - Variable Types - Online Tutorials Library

    Each variable in Java has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be …

  5. DEV Community
    https://dev.to › kmartitaこの結果を翻訳する

    Java Variables: A Complete Guide (feat. var Type …

    2025年5月17日 · This article provides a complete overview of Java variables, covering everything from basic concepts to modern features like local variable …

  6. upGrad
    https://www.upgrad.com › blog › types-of-variables-in-javaこの結果を翻訳する

    Types of Variables in Java: Code Smarter, Not Harder - upGrad

    2025年8月13日 · In this blog, we break down the key types of variables in Java, providing simple explanations, real-world examples, and use cases to enhance your coding confidence and clarity.

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  8. Guru99
    https://www.guru99.com › java-variables.…この結果を翻訳する

    Java Variables and Data Types - Guru99

    2024年11月22日 · What is a Variable in Java? A variable can be thought of as a container which holds value for you during the life of your program. Learn Java …

  9. tpointtech.com
    https://www.tpointtech.com › java-variab…この結果を翻訳する

    Java Variables - Tpoint Tech

    2026年1月2日 · Every variable must be assigned a data type to define the kind of data it can hold. In Java, variables are categorized into three types: local, …

  10. Tutorial Kart
    https://www.tutorialkart.com › java › java …この結果を翻訳する

    Java Variables | Java Variable Types | Java Tutorials

    In this Java Tutorial, we explored the different types of variables in Java. We covered instance variables, static variables, local variables, and method …

  11. stackabyte.com
    https://stackabyte.com › tutorials › Java › java-data...この結果を翻訳する

    Java Data Types and Variables | Stack a Byte

    Learn Java data types and variables with examples of primitive types, reference types, and best practices for efficient programming.

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