threads in java interview questions and answers

First, let's talk about the differences between final, finally, and finalize.　　Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )?　　Third, the difference between static nested class and inner class is that the more you say, the better (the more general the interview questions are ).　　Fourth, the difference between and.　　Fifth, the difference between has

class hello{public static void Main (string[] ARS) {A ab = new B (); Executed here, results: 1a2bAB = new B (); Executed here, results: 1a2b2b}}A: the output is 1a2b2b; the static code snippet for a class can be thought of as code executed by the class for the first load (virtual machine load), and for class loading, the first thing to do is to execute the construction of its base class, and then perform its own construction.50, the Succession time class execution order question, generally is t

Some questions that are frequently asked during interviews with Java programmers on the Internet, although a little old, are still worth reading. 1. Let's talk about the differences between final, finally, and finalize. Final? Modifier (keyword) If a class is declared as final, it means that it cannot generate a new subclass and cannot be inherited as a parent class. Therefore, a class cannot be declared bo

). In the process of populating the handler, depending on your configuration, Spring will do some extra work for you: Httpmessageconveter: Converts the request message (such as Json, XML, and so on) to an object, converting the object to the specified response information. Data Transformation: Data conversion for a request message. such as string conversion to Integer, double, and so on. Data is initialized: Data is formatted for the request message. such as converting a string into a formatt

most cases, we only need to determine if the values are equal, and then compare them with the Equals method.There is also a equalsignorecase that can be used to ignore case comparisons. String s1 = "abc"; String s2 = "abc"; String s3= new String("abc"); System.out.println("s1 == s2 ? "+(s1==s2)); //true System.out.println("s1 == s3 ? "+(s1==s3)); //false System.out.println("s1 equals s3 ? "+(s1.equals(s3))); //true12. What is a string pool?As the name i

equalsignorecase that can be used to ignore case comparisons."ABC"; "abc"; String ("abc"); System.out.println (//true System.out.println (//false System.out.println (//true 12. What is a string pool?As the name implies, a string constant pool is used to store strings. It exists in the Java heap memory.Explains how a string pool exists in Java heap space and when we use different ways to cr

to Wangwei"$ Java-jar Blockchain-java-jar-with-dependencies.jar-add "Send 3.5 BTC to Wangwei"Print Blockchain$ Java-jar Blockchain-java-jar-with-dependencies.jar-printSummarizeIn this article we implement the Blockchain storage function, next we will implement the address, transaction, wallet, some of the functions of

finalize () method to sort system resources or perform other cleanup tasks. The finalize () method is called before the Garbage Collector deletes an object. 　Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )? An anonymous internal class is an internal class without a name. It cannot be extends (inherited) other classes, but an internal class can be used as an interface and implemented by another

example, a landing page, using the PO mode, will create a LoginPage class, the class will define the user name input box, password input box, login button webelenentFor the corresponding element to implement the corresponding method, the input box is used to input, you need to create a user name and enter the password method, so that the real page consistent, so the design concept is PO mode. The pagefactory belongs to the PO mode, which is used to initialize the page Class of each PO pattern i

overloading. 25th, can you inherit the string class? The string class is a final class and therefore cannot be inherited. 26th, when a thread enters an synchronized method of an object, can other threads enter other methods of this object? No, one synchronized method of an object can only be accessed by one thread. 27th, there is a return statement in try {}, so will the code in the finally {} after this try be executed, when it is executed, befor

1 . What are worker threads and SwingWorker and how do I use them? When a swing program needs to perform a long task, it is usually done using a worker thread. Each task executes in a worker thread, which is an instance of the Javax.swing.SwingWorker class. The SwingWorker class is an abstract class; You must define its subclasses to create a SwingWorker object, which is usually done using anonymous inner classes. SwingWorker provides some features of

. TreeSetthe largest and smallest elements can be obtained from. Summary: Collections.sort() provides a list that is sorted once. PriorityQueueand TreeSet Dynamic maintenance of the ordered collection.9. Copy ListThere are two ways to copy a list. One is to use a ArrayList constructor. 1 ArrayListnewArrayList The other is to use Collections.copy() . 12 ArrayListnewArrayListCollections.copy(dstList, srcList); It is important to

digits to accurately represent (even need infinity), and the double type of the value of only 64bit, the back of the number of bits will definitely bring error, can not get "mathematically accurate" results.2. Questions about the number of bits and ranges represented by each data type in JavaA : The conversion of data types in Java, from high-precision like low-precision conversion will have a loss of p

= In.readline ();//read a line of content while(Line! =NULL ) { if(Character.isletter (line)) I++; Else if(Character.isdigit (line)) J++; ElseF++; Line=In.readline (); K++} in.close (); System.out.println ("Letter" +i+ "number" +j+ "Space" +j+ "number of lines" +k)}Catch(IOException iox) {System.out.println ("Problem reading" +fileName); } }}4, if there is a string "6sabcsfs33", with the most rapid way to remove the character "ab3", can not use the

++;Parent.printvalue ();　　((child) parent). myvalue++;Parent.printvalue ();}}Operation Result:Summarize:When a subclass has the same method as the parent class, and a parent class variable refers to a subclass object, which method is called, determined by the object's own "true" type, that is, the object is a subtype, it calls the method of the subtype, it is the parent type, and it invokes the method of the parent type. This feature is actually a concrete representation of the object-oriented "

Java Basics 1. What are the features of object orientation? 1. Abstraction: Abstraction is to ignore those aspects irrelevant to the current target in a topic, so that you can pay more attention to the aspects related to the current target. Abstraction is not intended to understand all the problems, but to select a part of the problem. Abstract: Process abstraction and data abstraction. 2. Inheritance: Inheritance is a hierarchical model that connects

Question OneWrite a method that uses the above algorithm to generate a random integer of a specified number (for example, three). Answer: xn+1= (7^5*XN) mod (2^31-1)Program source code :import java.util.Random;import Java.util.Scanner; Publicclass Randomcount{ PublicStatic void Main (string[] args){Random rand=new random ();System. out. Print (" Please enter the number of random numbers you want to output:");Scanner in =new Scanner (System. in);int n,x;N=in.nextint ();X=rand.nextint (100); for

single-threaded program can not produce OutOfMemoryError exception, using multithreading will also appear outofmemeoryerror, because the stack is thread-private, line multithreading also overflow method area3, JVM stack space allocation over the General Assembly caused by what problemshttp://blog.csdn.net/qq_30739519/article/details/510425844. How to detect dead loops and deadlocks in the JVMDeadlock: http://www.cnblogs.com/ilahsa/archive/2013/06/03/3115410.htmlDead Loop: http://blog.csdn.net/s

The first one discusses object-oriented programming and its features, common questions about Java and its functionality, Java collection classes, garbage collectors, this chapter focuses on exception handling, Java applets, SWING,JDBC, remote method Invocation (RMI), servlet, and JSP. Exception handling

Jame Dean 2016-12-06 17:12 Basic Knowledge section (90 points) one, the single choice question (altogether 12 questions, each question 3 points, altogether 36 points. ) 1, Java is from (B) language improvement redesign. A) Ada B) C + + C) pasacal D) BASIC 2. Which of the following statements is correct (B) A Java program generates machine code after compiling B