java coding interview questions and answers for experienced

The basic course of Java language programming Practice Study Questions Reference answers 1th Chapter Java Programming Overview 1.9 Practice Study Questions 1, the Java running platform includes three versions, please select

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

Java exception architecture diagram and several interview questions, java architecture diagram questions 1. java exception Architecture The pink ones are checked exceptions, which must be captured by the try {} catch Block or dec

class redefined the same method in the parent class. The Override method must have a method name, a parameter list, and a return type that are identical. The Override method does not restrict access to the original method.does 6.Java support multiple inheritance? Java does not support multiple inheritance, and each class allows only one class to be inherited, but multiple interfaces can be implemented.7. W

project, a transaction is made into a service layer through AOP, which enables a business logic operation to be controlled in one transaction if it includes several database operations. 10.Hibernate How it works and why you use it. Principle:1. Read and resolve configuration files2. Read and parse mapping information, create Sessionfactory3. Open session4. Create transaction transaction5. Persistent operation6. Submission of services7. Close session8 off Sessionfactory Why to use:1. The encaps

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

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

10 classic Java interview questions and classic java questions 1. How does Java's HashMap work? HashMap is a key value for the data structure. Each key has a corresponding value. The key is to identify such a value. Based on the hashing principle, HashMap stores and obtain

? What is Futuretask? How to wake up a blocked thread? How do immutable objects help with multithreading? What does multi-threaded context switching mean? What thread scheduling algorithms are used in Java? What is the role of Thread.Sleep (0)? What is the Java memory model, which areas are thread-shared, and which are unshared What are optimistic and pessimistic locks? Why do I synchroniz

Java interview questions, java questions1/** 2 * write a function. It accepts an integer (assuming length) and returns an array. The length of the array is length, 3 * the content in the array is a random value ranging from 0 to (length-1) and cannot be repeated. 4*5 * If the length is 5, the array may be [, 4]. 6*7 *

Java interview questions, java questions 1. storage structures used by stacks and queues Chain storage and sequential Storage 2. understanding of time complexity and space complexityTime Complexity: Number of statement executions in an algorithm, which is T (n). When n ch

++;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 "

. 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

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

thread in the ready state by dispatching it to occupy the CPU and turn it into a running state. At this point, the system actually executes the thread's run () method.④ Blocking and waking threadsBlocking state (Blocked): A running thread enters a blocking state when it cannot continue running for some reason. These reasons include:(a) When a method of blocking type such as sleep () of a thread object is executed, the thread object is placed in a block set and waits for a timeout to automatical

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

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

establishes a dependency between the beans.Simply put, beans are objects that are initialized, assembled, and managed by the spring IOC container.The process of getting the Bean object, first loading the configuration file with resource and starting the IOC container, and then getting the bean object through the Getbean method, you can call his method.Scope of Spring Bean:There is only one shared bean instance in the Singleton:spring IOC container, which is generally the Singleton scope.Prototy

Java's current heat has declined, but there are still a lot of people who learn java. Java's post is also a lot of infiltration. So, those classic Java knowledge points, you can see the problem can say 123? Come and have a look.The difference between 1.JDK and JRE What is the difference between 2.final, finally, and finalize?3. The difference between threads and processesHow does the HashMap in 4.