java_Java面试题及答案.pdf

1 1 2 3 4 2 String byte int char long float double boolean short java lang String final StringBuffer 3 int Integer Java Int java Integer java int Java booleanBoolean charCharacter byteByte shortShort intInteger longLong floatFloat doubleDouble 1 12 null 4 String StringBuffer JAVA String StringBuffer String StringBuffer StringBuffer StringBuffers 5 java 6 ArrayList Vector LinkedList ArrayList Vector Vector synchronized ArrayList LinkedList 7 Collection Collections Collection Set List Collections 8 s1 s1 1 short s1 1 s1 1 short s1 1 s1 s1 1 s1 1 int short s1 1 s1 1 21 Math round 11 5 Math round 11 5 Math round 11 5 12 M ath round 11 5 11 round 1 2 floor 22 String s new String xyz String Object 23 4 j 1 j 1 j public class ThreadTest1 private int j 4 12 public static void main String args ThreadTest1 tt new ThreadTest1 Inc inc tt new Inc Dec dec tt new Dec for int i 0 i 2 i Thread t new Thread inc t start t new Thread dec t start private synchronized void inc j System out println Thread currentThread getName inc j private synchronized void dec j System out println Thread currentThread getName dec j class Inc implements Runnable public void run for int i 0 i 100 i inc class Dec implements Runnable public void run for int i 0 i 100 i dec 24 Java goto java java 25 run start start 5 12 JVM run 26 runtime exception ArithmeticException ArrayStoreException BufferOverflowException BufferUnderf lowException CannotRedoException CannotUndoException ClassCastException CMM Exception ConcurrentModificationException DOMException EmptyStackException IllegalArgumentException IllegalMonitorStateException IllegalPathStateExcepti on IllegalStateException ImagingOpException IndexOutOfBoundsException Missi ngResourceException NegativeArraySizeException NoSuchElementException NullPo interException ProfileDataException ProviderException RasterFormatException SecurityException SystemException UndeclaredThrowableException Unmodifiable SetException UnsupportedOperationException 34 implements concrete class implements 27 List Set Map Collection List Set Map 28 abstract method static native synch ronized 29 length String length length length String length 30 Set equals Set iterator equals Set equals equals 31 Constructor override Constructor Overriding Overloading 32 String String final 33 swtich byte long String switch expr1 expr1 switch case int short char byte long string swtich 34 try return try finally code 6 12 return return 35 2 8 2 3 36 x equals y true hash code hash code 37 Java 38 synchronized synchronized 39 Singleton Singleton Java Class Singleton private static private public getInstance public class Singleton private Singleton private private static Singleton instance new Singleton class public static Singleton getInstance return instance public class Singleton private static Singleton instance null public static synchronized Singleton getInstance if instance null instance new Singleton 7 12 return instance private static 40 Java C Java public static public 41 Java JAVA JAVA JAVA 2 JAVA IndexOutOfBoundsException null NullPointerException JAVA throw java lang Thowable 42 2 Java c Java Java 43 wait lock sleep Inter ruptedException notify JVM Allnotity 44 List Map List ArrayList Vector List 8 12 Map Map 45 JVM class JVM ClassLoader Java ClassLoader J ava 46 char java unicode char 16 47 Thread Runnable synchronized wait notify 48 Java 49 return i i2 when i i2 10 12 57 java Overriding Overloading Java Overriding Overloading 58 GC GC GC heap GC GC System gc GC Java GC 59 static i 10 class A a a i 10 60 java java Serializable implements Serializable FileOutputStream ObjectOutputStream ObjectOut putStream writeObject Object obj obj 61 static static method 62 clone Clone super clone 63 JAVA break return 64 List Map Set List Set Map key value value 65 5 BufferedReader er java lang java awt java io java util java sql Remote List Map Document NodeList BufferedWriter FileR