Java

2.1.1 Types of Java programs Application Program Applet Program The structure and operating environment are different.The former is a standalone program that requires an executor (called a virtual machine) to run.The latter is a

The object of the class in order to associate/include a T-type instance, if the member variable includes t*/T&, this design is called "Aggregation" (aggregation), and in T form, it is called "composition" (combination)1 //Combination Composition2

OverviewWidely refers to read and write operations on filesJava IO operations are not only read and write to files, but also read and write to strings, byte arrays, objects, basic data typesOperations are divided into bytes and manipulated by

If you use bash, modify ~/.bash_profile or~/.profile；If you use zsh, modify the ~/.ZSHRCAfter modifying these files, re-open terminal, the configuration will not be lostFirst make sure the JDK is installed:# # Check the present running Javawhich

Scene:Operation of the last result set list in paged query results add () or remove () operation, error: Java.lang.UnsupportedOperationExceptionError:java.lang.UnsupportedOperationException at Java.util.collections$unmodifiablecollection.add

Reference learning in Java talks about what reference thinkReference provides a way to interact with the JVM GC, referring to reference, which should have some nouns in the brain, GC, Referencequeue, SoftReference, WeakReference, Phantomreference,

The existing requirements are as follows:The value of a simple expression is obtained by means of a cmd.For example, enter Java Expression 3 + 4The results are: 7Code:Import Java.text.DecimalFormat;public class Expression {public static void Main

Import Java.text.SimpleDateFormat; Import Java.util.Date; import Java util. Calendar; Public class Test { public static void Main (string[] args) { SimpleDateFormat sdf1 = new SimpleDateFormat ("Yyyy-mm-dd ' T ' HH:mm:ss.  Sssxxx ")

1, object-oriented, everything objects, object-oriented three basic features: encapsulation, inheritance, polymorphism. Object-oriented programs are made up of classes that encapsulate the properties and behavior of objects. Encapsulation: Hides the

Knowledge Point IO Stream applied to set properties reflectionCreate a new file Config.properties in the project directory#one time only can run one methodclassname=demo03. Studentmethodname=study#classname=demo03.

"Survival or death" how to determine whether the object is alive? Two algorithms are given in this paper, namely, the reference counting algorithm and the accessibility analysis algorithm. Reference counting algorithm The idea of the

In the previous article on the LIBSVM process and the simple Java code test to explain, this article is simple to libsvm how to practice in the project short description, inappropriate places welcome you to correct.The first step is to adjust the

All exception types are subclasses of the Throwable class, which contains the exception class and the error class, and exception also includes checked exception and unchecked exception.The unchecked Exception:java compiler does not require that an

Java memory allocation and management is one of the core technologies of Java, before we introduced the Java memory management and memory leaks and Java garbage collection knowledge, today we go deep into the Java core, the detailed introduction of

Java Program Performance optimizationUnderstand the performance of the computer know that performance response is slow to reflect: interface pauses, jitter, unresponsive, etc.Performance features include: Execution Speed: whether the

ObjectiveAs a veteran developer, the logging framework must not be unfamiliar. And in almost all applications, there will be a variety ofThe log framework is used to record the running information of a program. And for a mature Java application,

Thread Pool BenefitsIn a business scenario, it is recommended that pooled objects be managed at this time if an object creation destruction overhead is relatively large.For example, threads, JDBC connections, and so on, in high concurrency scenarios,

20165210 Experimental Five network programming and security network programming and security one: experimental requirements:Two pairs of pair programming: Reference Http://www.cnblogs.com/rocedu/p/6766748.html#SECDSA The function

EnvironmentSpringboot 1.5.9.RELEASE + JDK1.8Configuration stepsTwo-step, 1 configuration data source 2 configuration monitoringDirectly on the code1 Configuring the data sourcePackage Com.company.project.support.druid;import

Overview of the File class:The file class is an object that encapsulates files and folders in the file system, and can manipulate files and folders through the idea of an object. The file class holds various meta-data information for files or