write a program to check if a key exists in a HashMap in Java collection
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write a program to check if a key exists in a HashMap in Java collection Given a HashMap and a key in Java, the task is to check if this key exists in the HashMap or not. Examples: Input: HashMap: {1=Java, 2=JavaHashMap, 3=JavaPrograme}, key = 2 Output: true Input: HashMap: {1=G, 2=e, 3=e, 4=k, 5=s}, key = 10 Output: false Recommended: Please try your approach on {IDE} first, before moving on to the solution. Using Iterator (Not Efficient): Get the HashMap and the Key Create an iterator to iterate over the HashMap using HashMap.iterate() method. Iterate over the HashMap using the Iterator.hasNext() method. While iterating, check for the key at that iteration to be equal to the key specified. The entry key of the Map can be obtained with the help of entry.getKey() method. If the key matches, set the flag as true. The flag value after iterating, contains the result. Below is the implementation of the above approach: Program 1: // Java program to check if a key exists // in a HashMap or
