core java interview programs

First roundPhone interview, while on the code pad to do the problem, while the interviewer to explain his ideas while writing code.First question: Given an int, returns true if it is power of 10, otherwise false.Recursion can be easily solved.Second question: Given an array and an integer s, returns all the pairs of integers that are added equal to s in the array.I originally used HashMap to save S-a[i] and then iterate through the array to find all t

What is the difference between a process and a thread? A process is a standalone (self contained) operating environment that can be viewed as a program or an application. A thread is a task that executes in a process. The Java Runtime environment is a single process that contains different classes and programs. Threads can be called lightweight processes. Threads require fewer resources to create and reside

(decorative mode), Flyweight (enjoy meta mode), proxy (proxy mode),Command (order mode), interpreter (interpreter mode), Visitor (visitor mode),Iterator (iterative sub-mode), Mediator (mediator mode), Memento (Memo mode),Observer (Viewer mode), State (status mode), strategy (policy mode),Template method (pattern mode), Chain of responsibleity (responsibility chain mode)Factory mode: Factory mode is a frequently used pattern, and classes implemented according to the factory pattern can generate

1. What is acitsag startup mode? For such a question, I will write an example myself. I will observe it to understand it. Activty supports four startup modes. Launchmode: Standard: each time a new activity window is started (New Operation) Singletop: if it is a target activity at the top of the stack, It will be opened directly. Otherwise, a new activity window (new) will be opened ). Singletask and singleinstance are basically the same. The difference is that if the root activity is set to sing

use R2 in addition to R1, ... So go on until you can divide it evenly. The last non-0 divisor is (A, b).Time complexity O (logn).String s = "a" + "B" + "C" + "D" + "E"; how many objects are created?1 of them. "A" is a constant and only the literal value is stored.What are the output results of the following programs?String str = "ABCDEFGH";System.out.println (str.dubstring (3,5));Answer: "DE"What's the difference between StringBuffer and StringBuilde

, beanpostprocessor will process it and automatically create a proxy object for the bean that satisfies the matching rule.http://blog.csdn.net/itomge/article/details/8861268http://uule.iteye.com/blog/894055Spring Weaving Concept Weaving (Weaving): The process of applying a facet (Aspect) to a target object to create a new proxy object, which generally occurs in the following time: compile time : When a class file is compiled, this requires a special compiler to do so, such as AspectJ's

1. Spring Benefits/Features Lightweight : Spring is lightweight, with a basic version of about 2MB. inversion of Control (IOC): Spring is loosely coupled through control inversion, and objects are given their dependencies rather than creating or locating dependent objects. aspect-oriented programming (AOP): Spring supports tangent-oriented programming and separates application business logic from system services. containers : Spring contains and manages the life cycle and co

Self-organized questions about the Java interview, please correct the error.1, the core idea of springControl inversion and tangent-oriented programmingCore modules of the 2,springReverse control and Dependency injection, bean configuration, and loadWhat is 3,scope?Scope is the scene in the IOC container to set the object or survival space, if the object is not i

filter can only be called once when the container is initialized (theinit method ).6 The role of the STRUTS2 core controllerThe role of Strutsprepareandexecutefilter :Responsible for intercepting all user requests specified by By default. Suppose the user requests a path with no suffix or suffix ending with a. Action, and the request is transferred to the STRUTS2 framework, otherwise the STRUTS2 framework will skip processing the request.The ability

The difference between JDK and JRE:A: The JDK is the Java language Development kit that contains the JRE and development Kit (Java,exe, etc.), the Java language of the runtime environment, including the JVM and the core class library, the JVM is a Java virtual machine, to en

the performance of the server. Caching mechanism of Hibernate1. The first level cache is also called the internal cache exists hibernate, belongs to the application transaction level cache 2. Level Two cache A) application and caching b) Distributed caching Conditions: The data will not be modified by the third party, the data size in the acceptable range, the data update frequency is low, the same data is frequently used by the system, non-critical data. (c) Implementation of third party

1. Describe the STRUTS2 implementation process.The Struts 2 framework itself can be broadly divided into 3 parts: The core controller filterdispatcher, the Business controller action, and the enterprise business logic components implemented by the user. The core controller Filterdispatcher is the foundation of the Struts 2 framework and contains the control flow and processing mechanisms within the framewor

. Easy to use -- JRE And JDK JRE (Java Runtime Environment) Including the core class libraries required by Java Virtual Machine (JVM Java Virtual Machine) and Java programs. To run a developed

What is the purpose of garbage collection in 1.Java? When does garbage collection take place?The purpose of garbage collection is to identify and discard objects that the app is no longer using to free and reuse resources.What will 2.system.gc () and RUNTIME.GC () do?These two methods are used to prompt the JVM for garbage collection. However, starting or delaying a garbage collection immediately depends on the JVM.When is the 3.finalize () method cal

ext.: http://blog.csdn.net/wenwen360360/article/details/54969418ApplicationThe ―java application is a Java program that can run independently.Executed by the Java interpreter control.appletsThe ―java applet "cannot be run independently (embedded in a Web page).Performed by a Java