JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: How to search a key in Hashtable?


Description:

Below example shows how to search a key from the Hashtable. The method containsKey() helps us to find whether the specified key exists or not.


Code:
package com.java2novice.hashtable;

import java.util.Hashtable;

public class MyHashtableKeySearch {

	public static void main(String a[]){
		Hashtable<String, String> hm = new Hashtable<String, String>();
		//add key-value pair to Hashtable
		hm.put("first", "FIRST INSERTED");
		hm.put("second", "SECOND INSERTED");
		hm.put("third","THIRD INSERTED");
		System.out.println(hm);
		if(hm.containsKey("first")){
			System.out.println("The Hashtable contains key first");
		} else {
			System.out.println("The Hashtable does not contains key first");
		}
		if(hm.containsKey("fifth")){
			System.out.println("The Hashtable contains key fifth");
		} else {
			System.out.println("The Hashtable does not contains key fifth");
		}
	}
}

Output:
{third=THIRD INSERTED, second=SECOND INSERTED, first=FIRST INSERTED}
The Hashtable contains key first
The Hashtable does not contains key fifth
<< Previous Program | Next Program >>

List Of All Hashtable Sample Programs:

  1. Basic Hashtable Operations.
  2. How to iterate through Hashtable?
  3. How to copy Map content to another Hashtable?
  4. How to search a key in Hashtable?
  5. How to search a value in Hashtable?
  6. How to get all keys from Hashtable?
  7. How to get entry set from Hashtable?
  8. How to delete all elements from Hashtable?
  9. How to read elements using Enumeration in Hashtable?
  10. Hashtable implementation with equals and hashcode example.
  11. How to fetch values with user define object as keys in Hashtable?
  12. How to eliminate duplicate keys (user defined objects) with Hashtable?
Knowledge Centre
Class, Constructor and Primitive data types
Class is a template for multiple objects with similar features and it is a blue print for objects. It defines a type of object according to the data the object can hold and the operations the object can perform. Constructor is a special kind of method that determines how an object is initialized when created. Primitive data types are 8 types and they are: byte, short, int, long, float, double, boolean, char.
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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