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Module 9: Advanced Core Features

Lesson focus

String Pool & Memory Management

Understand interning, immutability, and when to reach for StringBuilder.

The string pool reuses literals to save memory; new String("x") bypasses the pool unless interned manually.

String concatenation inside loops creates garbage; use StringBuilder or StringJoiner.

Immutability enables thread safety and caching but requires mindful API design (avoid exposing char arrays).

Lesson quiz

Which class should you use for heavy concatenation?

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