
- Java Generics Tutorial
- Java Generics - Home
- Java Generics - Overview
- Java Generics - Environment Setup
- Examples - Generic Classes
- Java Generics - Generic Classes
- Type Parameter Naming Conventions
- Java Generics - Type inference
- Java Generics - Generic Methods
- Java Generics - Multiple Type
- Java Generics - Parameterized Types
- Java Generics - Raw Types
- Examples - Bounded Type
- Bounded Type Parameters
- Java Generics - Multiple Bounds
- Examples - Collections
- Java Generics - Generic List
- Java Generics - Generic Set
- Java Generics - Generic Map
- Examples - Wild Cards
- Upper Bounded Wildcards
- Generics - Unbounded Wildcards
- Lower Bounded Wildcards
- Generics - Guidelines for Wildcards
- Type Erasure
- Java Generics - Types Erasure
- Java Generics - Bound Types Erasure
- Unbounded Types Erasure
- Java Generics - Methods Erasure
- Restrictions on Generics
- Java Generics - No Primitive Types
- Java Generics - No Instance
- Java Generics - No Static field
- Java Generics - No Cast
- Java Generics - No instanceOf
- Java Generics - No Array
- Java Generics - No Exception
- Java Generics - No Overload
- Java Generics Useful Resources
- Java Generics - Quick Guide
- Java Generics - Useful Resources
- Java Generics - Discussion
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
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Java Generics - No Static field
Using generics, type parameters are not allowed to be static. As static variable is shared among object so compiler can not determine which type to used. Consider the following example if static type parameters were allowed.
Example
package com.tutorialspoint; public class GenericsTester { public static void main(String[] args) { Box<Integer> integerBox = new Box<Integer>(); Box<String> stringBox = new Box<String>(); integerBox.add(new Integer(10)); printBox(integerBox); } private static void printBox(Box box) { System.out.println("Value: " + box.get()); } } class Box<T> { //compiler error private static T t; public void add(T t) { this.t = t; } public T get() { return t; } }
As stringBox and integerBox both have a stared static type variable, its type can not be determined. Hence static type parameters are not allowed.
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