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Program: Write a simple generics class example.
Below example shows how to create a simple generics class. We have created SimpleGeneric
class, which accepts single type parameter. Look at the generics class definition, the type parameter should
be followed by class name and should contain with in <>, here T defines the type parameter. You can find
comments at example itself.
package com.java2novice.generics;
public class MySimpleGenerics {
public static void main(String a[]){
//we are going to create SimpleGeneric object with String as type parameter
SimpleGeneric<String> sgs = new SimpleGeneric<String>("JAVA2NOVICE");
sgs.printType();
//we are going to create SimpleGeneric object with Boolean as type parameter
SimpleGeneric<Boolean> sgb = new SimpleGeneric<Boolean>(Boolean.TRUE);
sgb.printType();
}
}
/**
* Here T is a type parameter, and it will be replaced with
* actual type when the object got created.
*/
class SimpleGeneric<T>{
//declaration of object type T
private T objReff = null;
//constructor to accept type parameter T
public SimpleGeneric(T param){
this.objReff = param;
}
public T getObjReff(){
return this.objReff;
}
//this method prints the holding parameter type
public void printType(){
System.out.println("Type: "+objReff.getClass().getName());
}
}
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| Output: |
Type: java.lang.String
Type: java.lang.Boolean
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Java Generics Sample Code Examples
- Write a simple generics class example.
- Write a simple generics class example with two type parameters.
- How implement bounded types (extend superclass) with generics?
- How implement bounded types (implements an interface) with generics?
- What is generics wildcard arguments? Give an example.
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ServletOuptputStream Vs PrintWriter
ServletOutputStream: ServletResponse.getOutputStream() returns a ServletOutputStream
suitable for writing binary data in the response. The servlet
container does not encode the binary data, it sends the raw data
as it is.
PrintWriter: ServletResponse.getWriter() returns PrintWriter object which sends
character text to the client. The PrintWriter uses the character
encoding returned by getCharacterEncoding(). If the response's
character encoding has not been specified then it does default
character encoding.
If you don’t make mistakes, you’re not working on hard enough problems. And that’s a big mistake.
-- Frank Wilczek
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