Reference Types

Strong, Weak, Soft, Phantom references

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Reference Types

Java provides different reference strengths to control GC behavior.

  • Strong: Default reference
  • Soft: Memory-sensitive caches
  • Weak: GC when weakly reachable
  • Phantom: Cleanup hooks

Code Examples

Weak reference usage

java
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2WeakReference<User> ref = new WeakReference<>(new User());
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Use Cases

  • Caching
  • Memory-sensitive applications

Common Mistakes to Avoid

  • Using weak references incorrectly