Java

the difference between collection and collections:1, Java.util.Collection is a collection interface . It provides a common interface method for basic manipulation of collection objects. The collection interface has many specific implementations in

Basic data typesIn data types, the most common and basic data types are called basic data types. You can use these types of values to represent some simple states.There are 8 basic data types for the Java language, the following are the 4 categories

Compared to the lock and volatile described earlier, the read and write to the final domain is more like normal variable access. For the final domain, the compiler and processor are subject to two reordering rules: Writing to a final field

First, let's say: overloading (overloading)(1) method overloading is a means of allowing classes to handle different types of data in a uniform manner. Multiple functions with the same name exist at the same time, with different number/types of

In Java:= = is an operator that compares two variables for equality.Equals, is a method of the Objec class that compares two objects for equality, and the Equals method of the Default object class is to compare the addresses of two objects, just as

java-input/output stream1 , input and output:Input/output (Input/output) refers to the input or output of data to a device or environment. Any language has the function of input and output, in the Java program, through the stream to complete the

Array Advantages: Fast query, if you know the index can quickly access the disadvantage: Delete slow, size fixed ordered array advantages: Faster than unordered array lookup disadvantage: Delete and insert slow, size fixed stack advantages: Provide

Click to enter _ more _java thousand ask1. How to represent floating-point values with binaryBefore we know how to express a floating-point value in binary, we need to know how to represent integer values in binary notation: How to represent integer

1.1 Variable parameters of the methodAfter JDK1.5, the number of parameters can vary when defining a methodSyntax: Add 3 points after the last data typeAttention:1. The variable parameter can only be at the end of the parameter list;2. A method can

Method One:Uppercase and lowercase letters are subtracted from the ASCII code table by a value of 32It is possible to convert a string into a character arraylowercase to uppercase minus 32Uppercase to lowercase plus 32String s= "good";Char[] C =

One, file creates filesFile File = new file ("D:" + file.separator + "Yi.txt");code example: PackageCom.hbut.io;ImportJava.io.File;Importjava.io.IOException; Public classFiledemo { Public Static voidMain (string[] args) {File file=NewFile ("D:" +

Click to enter _ more _java thousand ask1, how to monitor the operation of the JVMUnderstanding the JVM memory model look here: What is the Java memory modelUnderstanding JVM Memory Management Look here: How the JVM manages memoryUnderstanding the

Java Web framework------------------struts2 (website Tutorial version Helloworld)We all know that struts is one of the three most common Java Web frameworks, plus spring, Hibernate. Learning Struts is a must.To! So how to learn it? My advice is to:1,

Now only to understand java8, is not after the understanding of the point?New programming techniques, individuals do not like the first time to follow up.Is it more cost-effective to have practice in the community?A little shrewd Consideration. Not

Writing high-quality code: 151 suggestions for improving Java programs (Chapter 1: classes, objects, and Methods ___ 31 ~ 35), java151 If you read many books without thinking about them, you will feel that you know a lot. When you read a lot of

Thinking logic of computer programs (36) and thinking 36 In the previous section, we introduced the basic concepts and principles of generics. In this section, we will continue to discuss generics and the wildcard concepts in generics. Wildcards

JAVA communication series 1: Java Socket Technology Summary, logging ocket This document describes how to learn about java Socket.1 Socket communication Principle 1.1 ISO layer-7 Model 1.2 layer-5 TCP/IP Model   The application layer is equivalent

Conversion between JSON strings and java objects [json-lib] And jsonjson-lib During development, data is often exchanged with other systems. The data exchange formats include XML and JSON. JSON, as a lightweight data format, is more efficient than

Business Department interview (Ali), Business Department interview ali I. Java Basics 1. What are the differences between the instance method and the static method? 2. What types of exceptions are involved in Java? How to use them separately? 3.

[Java Study Notes] Chapter 4 of Java core technologies    Chapter 5 basic concepts of objects and classes 4th and objects Describes the basic concepts of classes and objects and the relationship between classes. Many objects in the program come from