Worked on the google/guava repository to enhance the stability and correctness of collection utilities, focusing on the Multisets.sum method. Addressed a critical overflow issue by implementing logic to saturate per-element counts at Integer.MAX_VALUE, ensuring that summing operations never produce negative counts or related exceptions. This approach aligned the summation behavior with the existing size() method, which already used IntMath.saturatedAdd for safe arithmetic. Comprehensive unit tests were added to verify that sums remain within safe bounds. The work relied on strong knowledge of Java, data structures, and unit testing to deliver a robust fix that improves downstream reliability.