core java questions

implemented at the core of the interface is Javax.servlet.Servlet. Each servlet must either implement this interface directly or indirectly, or inherit Javax.servlet.GenericServlet or Javax.servlet.http.HTTPServlet. finally, the servlet uses multithreading to serve multiple requests in parallel.What is the difference between 93.Applet and servlet?Applets are client-side Java programs that run on the client

deep understanding of Java Virtual Machine JVM advanced features and Best Practices (second Edition) core notes JAVA Environment: Java Virtual machine Advanced Features:One: Java memory area and memory exceptionA): Run data area 1: Procedure counter (Program Counter Regist

This blog is mainly for the ape friends to recommend a book, "Java multithreaded Programming core technology."The reason to recommend it, mainly because this book is very easy to understand, with examples throughout the book, so that the original concept of abstraction, understanding is no longer abstract.As long as you have a little bit of Java Foundation, you c

Recommendation of Java multi-thread programming Core Technology I wrote this blog to recommend a book "Java multi-thread programming core technology" to yuanyou. It is recommended mainly because it is easy to understand and runs through the entire book as an example, so that the original abstract concepts are not abs

platforms include:WindowsLinuxMacThe file is also very small, which can be decompressed directly at around kb. Supported features include:JD-core and JD-GUI are written in C ++, which is the precondition for the decompilation speed.JD-core does not need JRE.The decompilable version of JD-core is as follows:Jdk1.1.8Jdk1.3.1Jdk1.4.2Jdk1.5.0Jdk1.6.0Jikes-1.22Harmon

(throughput) collector? The throughput collector uses a parallel version of the new generation garbage collector, which is used for medium-sized and large-scale data applications. The serial collector is sufficient for most small applications, which require about 100M of memory on modern processors. 41. In Java, when can objects be garbage collected? This object can be recycled when the object becomes inaccessible to applications that currently use t

The main content index of this article1. Java Threads2. Threading Model3. Java thread pool4. Future (various future)5. Fork/join Frame6. Volatile7. CAS (Atomic operations)8, AQS (concurrent synchronization framework)9, synchronized (synchronous lock)10. Concurrent queue (blocking queue)This article only analyzes some of the core problems in

115 Java Interview Questions and answers-ultimate list (I), 115 java Object-Oriented Programming (OOP) Java is a computer programming language that supports concurrency, class-based, and object-oriented. The advantages of object-oriented software development are listed below: • Code development is modularized to fac

language Features, object-oriented (encapsulation, inheritance, polymorphism), reflection, generics ... (2) Java Class Library: Core class library, such as Io/nio, network, Utils ... ; Security libraries, JDK, management, and massive third-party class libraries (3) Java Virtual machines: garbage collector, Runtime, dynamic compilation, accessibility, such as JFR

The Spring framework is now almost a standard framework for Java WEB development. So, as a Java programmer, how much do you know about Spring's main technical points? You may want to use the questions in this article to check.1. General questions1.1. What are the main features of different versions of the Spring Framework?Versionfeaturespring 2.5 was released in

execution.Surround notification is one of the most common types of notifications. Most interception-based AOP frameworks, such as Nanning and JBOSS4, provide only surround notifications.The concept of pointcut (pointcut) and connection point matching is the key to AOP, which makes AOP different from other old technologies that simply provide interception functionality.The pointcut enables the location notification (advice) to be independent of the OO hierarchy. For example, a around notificatio

-daemon threads end, the program ends, the JVM ends, because the thread that needs to be guarded is gone, the daemon thread is not working, so the program ends and the program "Kill" the daemon thread. In layman's terms, the program will not end as long as a non-daemon thread exists in the program.In the Java language, the daemon thread generally has a lower priority, it is not provided only by the JVM, and the user sets the daemon itself when writing

original address.Redirect is the server based on logic, send a status code, tell the browser to request the address again, in general, the browser will use all the parameters just requested again, so the session,request parameters can be obtained.3 The difference between a dynamic include and a static include in a JSPA collection of questions and answers about Java technology delivered inside the companyDy

class does not have a way to modify the strings, if you really want to change them The following expressions are legal The = = operator detects whether two strings are placed in the same position In fact, only string constants are shared, and the results of operations such as + or substring are not shared Issupplementarycodepoint (int codepoint) is a Boolean method of the character class that determines whether the specified character (Unicode code point) i

Computer questions (Elementary)-Java Network Operations-printing web pages (Java) Print a webpage and be familiar with Java Network Programming: import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.MalformedURLException;import java.net.URL;

At present, multi-core CPU is the mainstream. The multi-core technology can effectively leverage hardware capabilities and improve throughput. For Java programs, concurrent garbage collection can be implemented. However, Java uses multi-core technology to bring about some pr

servletcontext =this.getservletcontext ();(commonly used)The role of ServletContext(1) Get the global initialization parameters of the Web applicationConfiguring initialization parameters in Web. xmlGet parameters from the context object(2) get the absolute path to any resource in the Web AppString path =context.getrealpath (relative to the Web app's relative address);Create a file a.txt under WebContent, create a b.txt under Web-inf, create a c.txt under SRC, and when the relative path is pass

is used for medium-sized and large-scale data applications. The serial collector is sufficient for most small applications, which require about 100M of memory on modern processors.41. In Java, when can objects be garbage collected?This object can be recycled when the object becomes inaccessible to applications that currently use the object.Is there a garbage collection in the permanent generation of 42.JVM?Garbage collection does not occur in a perma

asynchronously, then under what circumstances with the Execute or Submmit method? such as multi-threaded parallel execution, do not need to execute the results returned when the general use of the Execute method, if the need for multi-threading parallel computation, and all need to return the results of the time, need to Submmit method, of course, submmit generally blocking, If you want to retrieve the results at the time set, if you do not get the exception is to set the parameters through the

1. Threads and processesThere are many examples of processes and threads, because it is a learning note, that is, I feel very good understanding, is that we use the QQ every day, But we run the QQ.exe program, the process begins, we can open the Chat window at the same time, can be more than one video, and even the video side of the manual chat (maybe the sound is broken ...) Each of these tasks can be fully understood as a "thread" in the work, music, image emoticons, files and other functions