Common Java Pitfalls
4 Topics
1
String Comparison Mistakes
Understand the differences between reference identity and value equality, and how the JVM String Pool behaves.
A core junior-to-mid level interview filter. Expect questions on the String Pool, behavior of intern(), and safe null comparisons.
2
Concurrency Mistakes
Learn about race conditions, deadlocks, and the dangers of double-checked locking without volatile.
Commonly tested for senior and backend positions. Focuses on deadlock structures, volatile memory visibility, and double-checked locking safety.
3
Collection Mistakes
Understand the ConcurrentModificationException, custom key mutation issues, and different list initialization APIs.
Commonly tested. Expect questions on how ArrayList raises modification exceptions, hash collisions, and the difference between Arrays.asList() vs List.of().
4
Resource Leaks
Prevent leaks of database connections, file handles, and memory through proper resource management.
Critical for high-performance systems engineering. Expect questions on try-with-resources, AutoCloseable contracts, and common Java memory leak patterns.