Java Collection, HashMap Exercises: Associate the specified value with the specified key in a HashMap

Java Collection, HashMap Exercises: Exercise-1 with Solution

Write a Java program to associate the specified value with the specified key in a HashMap.

Sample Solution:-

Java Code:

import java.util.*;  
public class Example1 {  
  public static void main(String args[]) {  
  HashMap<Integer,String> hash_map= new HashMap<Integer,String>();  
  hash_map.put(1, "Red");
  hash_map.put(2, "Green");
  hash_map.put(3, "Black");
  hash_map.put(4, "White");
  hash_map.put(5, "Blue");
  for(Map.Entry x:hash_map.entrySet()){  
   System.out.println(x.getKey()+" "+x.getValue());  

Sample Output:

1 Red                                                                  
2 Green                                                                
3 Black                                                                
4 White                                                                
5 Blue

Java Code Editor:

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Java: Tips of the Day

Choice between Float and Double:

Data type Bytes used Significant figures (decimal)
Float 4 7
Double 8 15

Double is often preferred over float in software where precision is important because of the following reasons:
Most processors take nearly the same amount of processing time to perform operations on Float and Double. Double offers far more precision in the same amount of computation time.

Ref: https://bit.ly/3oj7K2K