java问题集合.doc

1. Windows (Notepad) Java.java(*.*)2. Java by valueby referenceAll parameters (values of primitive types, and values that are references to objects) are passed by valueJLS sect 8.4.1 Java, (by value), Java(by reference): (int, float, char)by value(Object)by value of reference to object3. Stringclassfinal String, , Stringfinal4. finalizersC+ destructors?Java (C+ ) destructors finalize()methodfinalize() null dispose() 5. class FrotzNo constuctor Frotz() in the class classconstructorcall constructor Java superclass constructor superclass constructor , API6. charintchar c = Aint i = c/c = (char) I7. applet, web serverclassclassweb serverclasspackageweb serverclassCOM.foo.utilpackageweb serverapplet codebase COM/foo/util()web server(searchreadexecute)8. Applet Panel Canvas, 9. Applet (MenuBar/Menu)Appletinit() Frame instance Menus Menubar (setMenuBar() Frame)AppletFrameContainer parent = getParent();while (! (parent instanceof Frame) )parent = parent.getParent();Frame theFrame = (Frame) parent;MacbrowsersJDK 1.1popup menuFrame10. String =reference, (address)if (s1.equals(s2) )or if (s1.equalsIgnoreCase(s2) )or if (s1.startsWith(s2) )or if (s1.endsWith(s2) )or if (s1.regionMatches(s1_offset, s2, s2_offset, length) )or if (pareTo(s2) 0)11. (float) ? Float Float One;Float Two;Float Hard = One + Two; float Float Java , classfloat One;float Two;float Hard = One + Two;Float One = new Float(1.0);Float Two = new Float(2.0);Float Hard = new Float(One.floatvalue() + Two.floatvalue();12. Stringint1) int i = Integer.parseInt(String); i = Integer.parseInt(String,int radix);2) int i = Integer.valueOf(my_str).intvalue();: Double, Float, Long13. int String1) String s = String.valueOf(i);2) String s = Integer.toString(i);3) String s = + i;Double, Float, Long 14. 1) RandomAccessFile fd = new RandomAccessFile(file,rw);fd.seek(fd.length(); fd method2) FileOutputStream(String nameboolean append) throws IOException constructor15. Java 2(JDK1.2)Java 2PATHJAVA_HOMEJDK1.1JAVA_HOMEJVMJava 2Solaris setenv JAVA_HOME Java2setenv PATH $JAVA_HOME/bin:$PATHWindowsset JAVA_HOME=Java2set PATH=$JAVA_HOMEbin;%PATH%16. JavaJava 2Java,InpriseJbuilderSymantecVisual Cafe,SybasePowerJJava 217. NetscapeIEJava applet,java appletJVMJDKNetscapeIEJava appletJDKappletviewerSunHotjavaappletappletappletviewerHotjavaJDKHotjava SunJava PluginappletHotjavaappletviewerapplet18. Java,PC:Java 2java.ioFilelistRoots()19. Runtime.exec(ls)Runtime.execProcessRuntime.execIO(stdinstdoustderr)Process.getOutputStream()Process.getInputStream()Process.getErrorStream()streamRuntime.exec(ls):tryprocess = Runtime.getRuntime().exec (command);InputStreamReader ir=newInputStreamReader(process.getInputStream();LineNumberReader input = new LineNumberReader (ir);String line;while (line = input.readLine () != null)System.out.println(line);catch (java.io.IOException e)System.err.println (IOException + e.getMessage();20. ObjectOutputStreamobjectObjectInputStreamobjectStreamCorruptedException:serializetionObjectOutputStreamObjectInputStreamObjectOutputStreamObjectInputStreamobjectObjectInputStreamdeserializeObjectOutputStreamStreamCorruptedExceptionObjectOutputStreamwriteStreamHeader()writeStreamHeader()objectsuper.writeStreamHeader()objectObjectOutputStream.reset()21. (serialization),: ,ByteArray/java.io.ByteAr