In March 2025, Jaejun Jeong developed a focused feature for the CODE-U-S/Coding_Test_Study repository, implementing a Java Solution class to address a basic arithmetic problem. He created a method, solution(int num1, int num2), that returns the integer quotient of two numbers, providing a clear and efficient approach to quotient calculation. The work demonstrated solid understanding of Java and algorithmic problem-solving, with changes tracked across two commits to ensure traceability and facilitate code review. While the scope was limited to a single feature and did not involve bug fixes, the implementation was clean, testable, and ready for integration into evaluation pipelines.