🚀 #09: Demystifying Reference Types

Curriculum: Hon-Gong-Ja (Java for Self-Study) Chapters: Chapter 05 (Sec 01, 02, 03) Duration: 2026-03-19 ~ 2026-03-27 (1st Reading) 1. Reference Types & NullPointerException A reference variable (Array, Class) being null means it does not hold any memory address. The Risk: Accessing or storing data (e.g., arr[0] ) while it's null triggers a NullPointerException . The Fix: You must create the object in memory using the new operator first. Analogy: It’s like pressing buttons on a remote contro