trojan horse summary

; } }Attention:　　When an object is stored in the HashSet collection, it is not possible to modify the fields in the object that are participating in the hash value, otherwise the hash value after the object has been modified is different from the hash value originally stored in the HashSet collection, in which case Even if the Contains method uses the object's current reference as a parameter to retrieve an object from the HashSet collection, the result of the object cannot be found, which al

); System.out.println (Stu+".." +addr); } //The second method of removal EntrySetSetHm.entryset (); IteratorEntryset.iterator (); while(Iter.hasnext ()) {Map.entryIter.next (); Student Stu=Me.getkey (); String Addr=Me.getvalue (); System.out.println (Stu+"........."+addr); } }}tips for using collections:1, see array is the structure of arrays, there is a corner mark, query speed quickly.2, see link is linked list structure:The deletion speed is fast, and has the unique method:AddFirst

); } bufr.close (); S.close (); }}/*server: Source: Socket read stream. Purpose: the socket output stream. It's all text and decorations. */classtransserver{ Public Static voidMain (string[] args)throwsexception{ServerSocket SS=NewServerSocket (10005); Socket s=ss.accept (); String IP=s.getinetaddress (). gethostaddress (); SYSTEM.OUT.PRINTLN (IP+ ".... Connected"); //reads the data from the socket read stream. BufferedReader Bufin =NewBufferedReader (NewInputStreamReader (S.getinputst

(LOCKB)}Synchronized (LOCKB){Synchronized (Locka)}Example 2:sychronized void Show (){Method ();}sychronized void Method (){Show ();}The lazy type in singleton mode, that is, lazy loading, when there is multi-threaded access, there will be a thread security problem. The workaround is to add synchronous code blocks or synchronous functions.However, after joining the synchronization, the efficiency of the program is reduced, as each thread enters the synchronization section and the synchronization

Char*name;//Name 8 }; //Alignment Algorithm//can store 3 structure variables, 16 bytes per struct variable /*int No;//ordinal 4 char *name;//name 8 int score;//Points 4*/ structRankrecord records[3] = { {1,"Jack", the}, {2,"Jim", -}, {3,"Jake", -} }; records[0].no =4; //wrong wording//Records[0] = {4, "Rose", 9000};Vii. 1. The definition of a pointer to a structstruct student{ intstruct Student *p;2. Use pointers to access members of the struct

methods in the object at the same time. At this point, the synchronized method of the different object instances is not interfering. In other words, other threads can access the Synchronized method in another object instance of the same class at the same time;2, is the scope of a class, synchronized static astaticmethod{} prevents multiple threads from accessing the synchronized static method in this class at the same time. It can work on all object instances of the class.2, in addition to the

into sleep. This thread will not run for a specified period of time.2. Suspend execution of the thread with suspend (). The "operational" status is not returned unless a resume () message is received.3. Suspend execution of the thread with Wait (). Unless the thread receives a notify () or notifyall () message, it does not become a "operational" state.4. The thread is waiting for some IO operations to complete.5. The thread tries to invoke the "synchronous" method of another object, but that ob

is can be called, not Lao Tzu's private Method) class and instance object, the class is equivalent to a container, the instance object is an external open interface, instance variable is derived from the class, but he is not a class, He's going to be able to invoke the properties of the class, give me the feeling class is the equivalent of a washing machine, washing machine has its own operation principle (class method), also has the roller (class property), the instance variable is the p

reflection.Array.getlength (Object obj);//Get array lengthArray.get (Object obj,int x);//Gets the elements in the array7. How to get the type of an element in an array,Example: int a = new int[3];object[] obj=new object[]{"ABC", 1};Cannot get the specific type of an array, only the type of one of the elements.such as: Obj[0].getclass (). GetName () got the java.lang.StringThe effect of reflectionCore issues to be solved by framework and frameworkI do the house to sell to the user, the user inst

) Creates a thread pool of a fixed number of threads.public static Executorservice Newcachedthreadpool () Creates a cacheable thread pool that calls execute to reuse previously constructed threads if the threads are available. If an existing thread is not available, a new thread is created and added to the pool. Terminates and removes from the cache those threads that have not been used for 60 seconds.public static Executorservice Newsinglethreadexecutor () Create a single-threaded executor.publ

not write immediately, but instead writes the cached data to the local disk according to the timestamp. So after calling the set method, it is possible that the data has not yet been written to the disk application to terminate. The above problem can be forced to write [defaults synchornize] by calling the Synchornize method; Nskeyedarchiver If the object is NSString, Nsdictionary, Nsarray, NSData, NSNumber and other types, you can archive and restore directly with Nskeyedarchiver not all

toString (int i,int radix): The I value of a certain binary, Converted to a string representation. Radix: binary Other decimal: public static int parseint (String s,int Radix) : Converts a binary string representation of S to a decimal int value. Radix is the binary number; Automatic packing and disassembly of 5.jdk5:1. Auto-Boxing: Converts the "basic data type" to the corresponding "wrapper type";Integer intobj = 10;2. Automatic unpacking: The "package type" is converted to the correspondi

of locationsAssignment Array.set (array,5,4) Gets the value of the array array.get (array,5); 1 Practice:2 Write a program that can execute the main method of the class using the user-specified class name. 3 Packagebolgtest;4 5 ImportJava.lang.reflect.Method;6 7 Public classBolgTest1 {8 Public Static voidMain (string[] args)throwsexception{9 TenClass cls = studenttest.class; Onemethod = Cls.getmethod ("main", string[].class); AMethod.invoke (NULL,Newobject[]{Newstring[]{"abc", "DGF"}}); -

System.out.println (Str.charat (1));Reflection Mode System.out.println (Charat.invoke (str, 1));If the first parameter of the Invoke () method passed to the method object is null what is the meaning of the method object that corresponds to a static approach4. Field classThe field class represents a member variable in a classThe field FIELDX represents the definition of x rather than the specific x variable.Sample code Reflectpoint point = new Reflectpoint (1,7); Field y = class.forname ("Cn.it

. Minimize debug, less debug, good programmers always spend 80% of the time to think about how to solve problems, 20% of the time to do the code, and bad programmers always spend 20% of the time to write code, 80% of the time to debug the code, before you try to think how to do, and has done a full experiment for your own ideas.2. As much as possible to improve the efficiency of debug, set the appropriate breakpoints, the use of shortcut keys.3.debug F6 shortcut keys are often used, it and Power

for monitoring processing Closeitem.addactionlistener (NewActionListener () { Public voidactionperformed (ActionEvent e) {system.exit (0); } });　　　　//The form itself listens for processing F.addwindowlistener (NewWindowadapter () { Public voidwindowclosing (windowevent e) {system.exit (0); } }); } Public Static voidMain (string[] args) {Newmymenutest (); }}Summarize:Event Monitoring mechanism:　1. Determine the event source (container or component)2. The listener is regi

transform stream. The Read method in the transform stream. has been integrated into the Code table, the underlying invocation of the Read method of the byte stream will fetch one or more bytes of data to be stored temporarily, and to check the specified encoding table, if the encoding table is not specified, check the default Code table. Then the Read method of the stream can return a character such as Chinese. The conversion stream has completed the encoding conversion action, for the direct o

exceptions are exceptions caused by improper program writing, the most common null pointer exceptions, array subscripts exceeding exceptions, and so on. Throws throws an exception if the exception is an inherited runtimeexception, you do not need to force you to write a try catch statement to ensure that the exception being thrown is handled. If you inherit exception, you will need a try catch statement to ensure that exceptions are handled, and common run-time exceptions are: C

class instance object in the outer methodThe process of creating an agent is changed to a more elegant way, writing a public object GetProxy (final Object target) method binding the receive target to return the proxy object at the same time, making the caller more lazy, more convenient, and the caller does not even have to touch any proxy APIThe system function code is modularized, and the cut-off code is provided by Parameter form, how to provide the system function code to be executed in the

cannot be accessed by an external file. extern: Indicates that this variable can be accessed by an external file. Effect on local variables: Static:1> extends the period of the variable and does not disappear as the function is destroyed. 2> extends the scope of variables.* (p++) and * (++P) are the same.Not the same. * (p++): First take the value of *p, then P plus 1* (++p): first P plus 1, then take *p 23. Why do I need a pointer variable type? Because each pointer variable may po