When Not to Use Java Parallel Streams

This video advises against using Java parallel streams in specific scenarios to ensure optimal performance. For example, if the data source (such as a linked list) is expensive or inefficient to split, parallel streams may not offer any advantage. Likewise, the overhead of starting threads for parallelism can negate the benefits, especially for smaller tasks or datasets. In addition, the cost of combining partial results—such as merging large sets—can also be prohibitive. Moreover, the utility of parallel streams diminishes on systems with fewer cores. Lastly, certain stream operations like 'iterate' and 'limit' are inefficient when parallelized due to synchronization overhead. Careful benchmarking and consideration of these factors are essential for effective use of parallel streams.