Run Length Encoding Data Compression Algorithm

Assume a string abbcccdddd is given, there can be a repetition of character, given string needs to be compressed according to repeating of character, the algorithm is also known as Run Length Encoding (RLE) Data Compression Algorithm.

package org.wesome.dsalgo;

public class CompressString {
     static String compressString(String string) {
        int sum = 1;
        String compressedString = "";
        for (int i = 0; i < string.length() - 1; i++) {
            if (string.charAt(i) == string.charAt(i + 1)) {
                sum++;
            } else {
                compressedString = compressedString + string.charAt(i) + sum;
                sum = 1;
            }
        }
        compressedString = compressedString + string.charAt(string.length() - 1) + sum;
        return compressedString;
    }
}

package org.wesome.dsalgo;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

public class CompressStringTest {
    @Test
    void CompressStringTest1() {
        String compressedString = "weesssoooommmmmeeeeee.......oooooooorrrrrrrrrgggggggggg";
        Assertions.assertEquals("w1e2s3o4m5e6.7o8r9g10", CompressString.compressString(compressedString));
    }
}

plugins {
    id 'java'
}

group = 'org.wesome'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = JavaVersion.VERSION_1_8

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter:5.6.2'
}

test {
    useJUnitPlatform()
}