I think a lot of it was for performance concerns. For math-heavy operations, the dealing with lots of objects caused quite a bit of garbage collection overhead. This is much less important now—they&#x27;ve optimized garbage collection to the point that it is often irrelevant—but it&#x27;s still a concern in math-heavy applications.<p>Here&#x27;s an article that goes into it in more detail:
<a href="http:&#x2F;&#x2F;www.javaworld.com&#x2F;article&#x2F;2150208&#x2F;java-language&#x2F;a-case-for-keeping-primitives-in-java.html" rel="nofollow">http:&#x2F;&#x2F;www.javaworld.com&#x2F;article&#x2F;2150208&#x2F;java-language&#x2F;a-cas...</a>