《 Here are the answers from Madai and Clkrst. my question is, what does the: java interface do? 1, read from the book is the Java Program interface only defines constants and empty methods, what
object, the object is called the Unreachable object (the surviving object, the object cannot be reclaimed). Otherwise, the unreachable object can be recycled.
2, how to clean up the new generation of garbage
Garbage Cleanup Algorithm
The new generation of garbage collectors often assume that most objects have a very short survival time, with only a few objects surviving longer. According to this assumption, the new generation of garbage removal algor
From: http://blog.csdn.net/hlf48641715/archive/2008/12/25/3605789.aspx
Several Java objects (PO, Vo, Dao, Bo, pojo)I. Po: persistence object of persistant object. It can be regarded as a Java object mapped to a table in the database. The simplest Po is to correspond to a record in a table in the database. A set of PO can be used for multiple records. The PO shou
(Exception e) {System.out.println (E.getmessage)) finally{SYSTEM.OUT.PRINTLN ("finally Running");//No matter what happens to the program, finally code blocks are executed.} SYSTEM.OUT.PRINTLN ("program running Here");}}1. The program is matched according to the type of exception. Automatically enter the appropriate catch statement. Exception should be placed after other exception statements, because they
I am a beginner in PHP. I have bought a java manual and haven't started to read it yet. This statement has made me very excited. I really want to know the specific situation. I am a beginner in PHP. I have bought a java manual and haven't started to read it yet. This statement has made me very excited. I really want to know the specific situation. Reply: "Father, forgive them for they don't know
Click to enter _ more _java thousand ask1. What is value passingValue delivery is the transfer of a value stored in a storage unit in memory space to another storage unit. (storage units in Java are not addresses of physical memory, but have dependencies)For example://定义了一个改变参数值的函数publicstaticvoidchangeValue(int x) {??
Click to enter _ more _java FAQ-base Class Library1, util package has what functionThe Java.util package provides the underlying tools classes in Java. Includes base classes such as the basic Set framework and common tool classes. Main classes such as:?The Java.util package is broadly divided into two categories: collections, tools, and the following are some of
What is a byte code?Bytecode can also be said to be a language, or an operational primitive that communicates with the operating system. The purpose of bytecode is actually to shield operating system differences, operating system differences to the professional virtual machine developers, they want to ensure that their development of virtual machines compatible w
What is the difference between an Ear, Jar, and war file? What kind of environment they are used separately.
In the file structure, the three are not different, they are in the zip or jar file compression format. But they are used for different purposes:
Jar file (with the extension. Jar) contains common libraries, resources, and auxiliary files (auxiliary files)
1> the reflection mechanism of Java is seldom used in the normal business development process, but it is widely used in the construction of some basic framework.2> What is the Java reflection mechanismThe
to use java.ext.dirs Path of extension directory or directories os.name Operating system name Os.arch Opera Ting system Architecture os.version Operating System version file.separator file separator ("/" on UNIX) Path.separator Pa Th separator (":" on Unix) Line.separator line separator ("\ n" on Unix) User.Name user's account name user.home user ' s hom E directory user.dir user ' s current working directoryAnd then reminds me of a long time ago a package to the method, Sun.arch.data.model ac
Click to enter _ more _java thousand ask1, >, >>, >>> what is the differenceSee Java operators here: What are the operators of JavaUnderstanding Java Operator Precedence See here: What is
I often hear about IOC and spring. What is IOC?
IOC can be understood as an implementation method of 'interface-Oriented Programming ide'. IOC implements mandatory 'interface-Oriented Programming '.
Spring forcesProgramImplement the class according to the architect's idea.
For example, the architect designs three business objects: users, data pools, and data elements. Architects want these three
Click to enter _ more _java thousand ask1. What are the annotations?Annotations in Java (Annotation), also called metadata. is a feature introduced in later versions of Java 5.Annotations and classes, interfaces, enumerations are at the same level, can be used to label packages, classes, fields, methods, local variable
Click to enter _ more _java thousand ask1. What is the difference between FULLGC, MINORGC and MAGORGC?FULLGC, MINORGC, MAGORGC, and YOUNGGC are the Java garbage Processing mechanism (GC) nouns, which are very simple to differentiate:
Laosheng is a garbage cleanup, known as FULLGC or MAGORGC.
A new generation o
Click to enter _ more _java thousand ask 1, what is the new generation of replication algorithm
Understanding heap Memory Look here: What is the Java heap memoryLearn about Java garbage collection look here:
The JavaScript programming language is developed by Netscape,inc., which is not part of the Java platform. JavaScript does not create small applications or standalone applications. In the most common form, JavaScript resides in HTML documents, providing a variety of web page interactions that are not possible with simple HTML. The main difference between
memory space resources, so that other variables to use it. In C + +, it is up to the programmer to release the memory space of the unused variables. This means that when a programmer thinks a variable is useless, it should write a code that frees up the memory it occupies. This minimizes memory leaks and resource waste.But this is obviously very cumbersome. Prog
getmessages () {return messages;}} This design is good? Suppose we repeat the same message to the record () method (the message comes from a different user, so you can treat each message as a new String ("...")), and the message content is large, then this design will greatly waste memory space, because the message list is recorded in the newly created, Sepa
What is the fastest Garbage Collector in Java 8?
OpenJDK 8 has multiple GCGarbage Collector) algorithms, such as Parallel GC, CMS, and G1. Which one is the fastest? What if I change the default GC of Java 8 from Parallel GC to G1
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