java programming interview questions and answers

method in a subclass that has the same name and parameters as its parent, we say that the method is overridden (override). When an object of a subclass uses this method, the definition in the subclass is called, and for it the definition in the parent class is "masked". If more than one method with the same name is defined in a class, they either have a different number of arguments or have different parameter types, which is called a method overload (overload).The overloaded method is a ty

some time ago because to participate in a written test, during the preparation of the online found two articles on the written topic, one of the In the process of finding these answers, I recorded the relevant answers and formed the following things. Need to explain that the following answer must have a lot of incomplete or even wrong place, need you to correct and perfect it, do not throw my eggs ah.I hope

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

XML interview questions include XSLT techniques for transforming XML files, xpath,xquery, and XML basics such as DTDs or schemas. This article will see 10 common XML interview questions and answers. Most of these questions are as

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

statement in try {}, so will the code in finally {} following this try be executed? When will it be executed, before or after return? Will be executed and executed before return. 28. Programming question: How can I calculate 2 by 8 in the most efficient way? Programmers with a C background are particularly fond of asking such questions. 2 29. The two objects have the same value (X. Equals (y) = true), but

? 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

requirements graphically in various phases of software development; IBMRational Rose is one of the many UML modeling tools in the requirements phase, often used in drawing examples, class diagrams, sequential graphs. 15. Describe the tool class that you exported, and indicate the maximum amount of data POI (combining cell objects and background color applications) Finally here also found some of Baidu Library interview

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

Java interview questions (the following lists the questions. For the answers, go to: Full Java interview questions (in )) 96. What are the

1 , what are the aspects of object-oriented features ?　　The object-oriented programming language has 4 main features: encapsulation, inheritance, abstraction, polymorphism, etc.Details:http://www.cnblogs.com/guweiwei/p/6599289.html2 , access modifiers public,private,protected, and what is the difference between not writing (the default)? 　　Defaults to default when members of a class do not write access adornments. The default is equivalent to exposing

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, before or after it? Will execute, before return.

++;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

we don't want to repeat, we should use set. (2) Some collection classes allow the initial capacity to be specified, so if we can estimate the number of storage elements, we could use it to avoid a hash or resize. (3) Based on interface programming, rather than on implementation programming, it allows us to easily change implementations later. (4) Always use type-safe generics to avoid classcastexception

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

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

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