Break CamelCase Challenge in Java

The challenge

Complete the solution so that the function will break up camel casing, using a space between words.


solution("camelCasing")  ==  "camel Casing"

Test cases

import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

public class SolutionTest {
    public void tests() {
      assertEquals( "Incorrect", "camel Casing", Solution.camelCase("camelCasing"));
      assertEquals( "Incorrect", "camel Casing Test", Solution.camelCase("camelCasingTest"));
      assertEquals( "Incorrect", "camelcasingtest", Solution.camelCase("camelcasingtest"));

The solution in Java

class Solution {
  public static String camelCase(String input) {
    String out = "";
    for (int i=0; i<input.length(); i++) {
      String c = Character.toString(input.charAt(i));
      if (c.equals(c.toUpperCase())) {
        out+=" ";
    return out;