Check out example codes for "hashmap get value by key java". It will help you in understanding the concepts better.

Code Example 1

import java.util.HashMap;
//Within a class
//You can do new HashMap<Key Type, Value Type>();, but you don't need to
HashMap<Int, String> examplehashmap=new HashMap<>();
//put in values
 examplehashmap.put(5, "example");
//get value
//returns "example"

Code Example 2

//Import Hashmap
import java.util.HashMap;
    HashMap<String, String> dir = new HashMap<String, String>();
//Add key, values  
    dir.put("hi", "hello");
	dir.put("wow", "amazing");
//print value for hi.

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