Are Java 8 Streams Really Slower Than Collections?

Streams vs Collections Performance in Java 8

Initial Benchmark

A developer conducted an informal benchmark to assess the difference in performance between Java 8 Streams and legacy Collections for filtering and mathematical operations on a list of integers. The result showed that Streams were about twice as slow as Collections, and parallel processing did not yield significant improvements.

Updated Results

Following suggestions to use JMH for benchmarking and warm up the JVM, the test was repeated numerous times. Surprisingly, the updated results indicated that Streams outperformed Collections.

Possible Explanations

• Choice of Data Structure: The use of LinkedList in the initial test may have negatively impacted performance. It is generally less efficient for random access and iterations compared to ArrayList for large lists.
• Intent of Streams: Streams are designed primarily for ease of coding and safety, rather than maximizing speed. They offer the ability to express data transformations and operations in a concise and type-safe manner.
• JIT Optimization: While JIT optimizations can inline functions from Streams, the resulting code may not be as efficient as carefully handcrafted manual implementations.

Benchmarking Cautions

Accurate benchmarking requires proper methodologies and tools. Avoid hand-written code and use libraries like JMH to ensure reliable results. Additionally, consider the context of your application and the specific operations you need to perform.

Conclusion

Streams offer a convenient and safe way to manipulate data, but they may not always be the fastest option. For performance-critical applications, manual implementations might be more suitable. However, Streams provide significant benefits in terms of code readability and maintainability, making them a valuable tool for developers.

The above is the detailed content of Are Java 8 Streams Really Slower Than Collections?. For more information, please follow other related articles on the PHP Chinese website!