2015 written interview experience--java Basics

1. The size of the nine basic data types, as well as their encapsulation class.

2. Can switch use string to make arguments?

Answer: Swith can use parameter types in the Java language: only convertible int values, strings or enum variables is permitted

can be automatically converted to an integer type (byte,short,int), a string type, an enumeration type.

Java cannot be a boolean,float,double,long of the switch parameter (cannot be converted directly to int).

3. The difference between equals and = =.

4. What are the common methods of object?

5. Java Four kinds of references, weak strength soft virtual, used to the scene.

6. The role of Hashcode.

7. The difference between ArrayList, linkedlist and vectors.

8. The difference between String, StringBuffer, and StringBuilder.

9. Features and usage of MAP, Set, List, Queue, stack.

The difference between HashMap and Hashtable.

HashMap and Concurrenthashmap differences, hashmap of the underlying source code.

The difference between TreeMap, HashMap and Lindedhashmap.

Collection package structure, and the difference between collections.

Do you have return,finally in Try Catch finally,try?

Excption and error packet structure. Oom What situation you have encountered, SOF what you have encountered.

Three features and meanings of Java-oriented objects.

The meaning of override and overload to distinguish.

The difference between interface and the abstract class.

The difference between static class and non static class.

The implementation principle of Java polymorphism.

21. Two ways to implement Multithreading: Thread and runable.

22. Thread synchronization method: Sychronized, lock, Reentrantlock and so on.

23. Level of Lock: Method Lock, Object lock, Class lock.

24. Write out the producer consumer model.

Threadlocal's design philosophy and role.

ThreadPool usage and advantages.

The other things in concurrent bag: Arrayblockingqueue, Countdownlatch and so on.

The difference between wait () and sleep ().

The ratio of foreach to normal for loop efficiency.

Java io and NiO.

31. The reflection acts on the principle.

32. Generic features,list<string> can be converted to list<object>.

33. Principles and features of several ways to parse xml: DOM, SAX, pull.

Compare Java with C + +.

Java1.7 and 1.8 new features.

36. Design mode: Single case, factory, adapter, responsibility chain, observer, etc.

Use of the Notoginseng. Jni.

2015 written interview experience--java Basics