1. JDK, JRE, and JVM: JDK is for Java development, JRE is for running Java applications, and JVM interprets Java bytecode.
2. OOP Principles in Java: Java implements OOP principles like encapsulation, inheritance, abstraction, and polymorphism.
3. Java Access Modifiers: Access modifiers control visibility; examples include public, private, protected, and default (no modifier).
4. static Keyword: static is used for class-level members and doesn't require an instance of the class for access.
5. final, finally, and finalize: final is for constants, finally is for code blocks, and finalize is a method for object cleanup.
6. Exception Handling in Java: Java uses try-catch blocks to handle exceptions and provides throw, throws, and finally for advanced handling.
7. Java Memory Management: Discuss heap and stack memory, and how Java's garbage collector manages memory.
8. equals() vs. ==: equals() compares object content, while == checks reference equality.
9. Java Design Patterns: Design patterns are reusable solutions; for instance, Singleton ensures a class has only one instance.
10. Multithreading in Java: Java supports multithreading using classes like Thread and keywords like synchronized, with potential issues including deadlock and race conditions.