CamelCase pattern matching in Java

In this tutorial we are going to learn about CamelCase pattern matching in Java. In this a list of CamelCase words will be there and a pattern will be there. So, we will be printing all the strings in that list matching that pattern. For example: –

array[]=[“CodeSpeedy”,”CodeSpeedyJava”,”CodeBlog”] and the pattern is “CS”. So, our code will print CodeSpeedy and CodeSpeedyJava.

So, we are going to follow certain steps: –

  1. We will be creating a hashmap.
  2. This HashMap will contain each word and it’s corresponding Uppercase letters as a string.
  3. After that we will match these Uppercase string with the pattern and print the corresponding word.

CamelCase Implementation

Now we are going to implement our code using Java.

Code: –

import java.util.*; 
class Main{ 
    //Function that takes List of words and a pattern
    static void PatternMatcher(ArrayList<String> word, String camelPattern) { 
        //Creating map of UpperCase letter and words
        Map<String, List<String>> ucmap = new HashMap<String, List<String>>(); 
        //Mapping words and their corresponding Uppercase string
        for (int i = 0; i < word.size(); i++) { 
            String s = ""; 
            int length = word.get(i).length();//Length of each word 
            for (int j = 0; j < length; j++) {
                //If our letter is Uppercase then we add that letter to the string s and map it to our word
                if (word.get(i).charAt(j) >= 'A'&& word.get(i).charAt(j) <= 'Z') { 
                    s += word.get(i).charAt(j); 
        boolean wordpresent = false; 
        for (Map.Entry<String,List<String>> mp : ucmap.entrySet()) { 
            if (mp.getKey().equals(camelPattern)) { 
                //if our key matches our pattern then word present is true and we print the corresponding string
                wordpresent = true; 
                for(String s : mp.getValue()) {
                    System.out.print(s +"\n");
        //If No word matches our pattern then we print this
        if (!wordpresent) { 
            System.out.println("No such word found with the corresponding pattern"); 
//Function to add as list   
private static List<String> list(List<String> list, String str) { 
    List<String> temp = new ArrayList<String>(); 
    if(list != null) 
    return temp; 
public static void main(String[] args) 
    String word[] = {"No", "NoProblem", "NotPossible", "NotPos", "NewPosition"}; 
    ArrayList<String> givenList = new ArrayList<String>(Arrays.asList(word)); 
    String camelCasePat = "NP"; 
    PatternMatcher(givenList, camelCasePat); 

Output: –


This is how we do CamelCase pattern matching.

Also Read: –

Convert array elements to camel case in Java

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