Java

Recently, in a systematic review of the knowledge of Java virtual machines, there is an interesting question: What is the type of Boolean in virtual machines? To answer this question, we look at the JDK source code is not able to solve the source

The problem with writing the Spark program today is that there was a mistake in reading the file: "Exception in Thread" main "java.nio.charset.MalformedInputException:Input Length = 1 "The code to read the file is as follows:A look at this wrong

The father of Java-James Goslin, born in Canada, is a computer programming genius. When he studied computer science at Carnegie Mellon University, he wrote a multiprocessor version of the UNIX operating system and was the founder of the Java

Chapter III Java's BASIC programming structure a simple Java application Access modifier public,private,protected The main method must be public-decorated, and C # does not have to Data type Floating-point numbers can be

Java data TypesThe data types in Java can be divided into two categories, reference types (reference types), and basic types (primitive types), with reference to the most recent definition of the Java Official document drawing type diagram

The following swing interface is attached!!! Please look forward to! Packagecom.yikuan.cn;Importjava.util.ArrayList;Importjava.util.Collections;ImportJava.util.HashMap;/*** To realize the function of simulated bucket landlord: * Combination card,

James Gosling:java's fatherWen/Pottery InscriptionsAs the father of Java, James Gosling's name is familiar. When people comment on a programming language, they always like to carry the hen that lays the egg together. Java is a popular style for

To do a file read write, you need to use a class: file, here is a simple record.Constructs the method, passes in a string, the absolute path and the relative path all can, the file name or the folder also can: Public File (String pathname)There are

Tag:==    method     has a    set   ring    Constant pool     address space     operation DEF = = =? 2.1.1===? How to understand variable thread safety inside a method, instance variable non-thread safe? In-method variables are local variables

The former in Ruan Yi Feng's blog saw this "similar image search principle" blog, there is a kind of impulse to realize these principles.Google "Similar image search": You can use an image to search all images on the internet that resemble it.To

Exceptions and Errors in JavaException mechanism in Java to better enhance program robustnessThrowable for top, Error and ExceptionError: Virtual machine errors, memory overflow, thread deadlockException:runtimeexception is null pointer exception,

Maven Project version number Default version number: 1.0-snapshot The best practice is to contract the version to an unstable version if the release must be deleted; Recommended version rule: Major version number. The minor version

Concurrency principlesingle-core system : Threads alternate execution, because of the alternating fast and many, giving people a feeling of simultaneous executionmulticore Systems : Not only can you alternately execute threads, but you can overlap

Java Script functiondefinition; a function is an event-driven or reusable block of code that executes when it is invoked. Basic format; Functionname (formal parameter) {code block}. Call function----------function name (argument);Knowledge point; 1.

1. Abstract abstractionWhat is abstract , Chinese is abstract, extract from concrete things, generalize their common aspect, essential attribute and relation, etc., call abstract. invisible, the touch of something called abstraction, abstraction is

java.lang.String; is a string type, the first thing to note about the string class is the following:1. Once the string is created, it cannot be changed. Once the "ABC" string object is created, it can no longer become "ABCD";2. Improve the access

learning without thinking is not the case, but thinking without learning is dangerous.I. Objects (object)1, the Machine model (program space), the actual problem solving problem model (problem space).2. We refer to the elements in the problem space

About the finally statement block, has the following characteristics:The 1.finally statement block can be directly associated with a try statement block. Try...finally ...2.try...catch...finally can also3. The code that is usually in the finally

The SortedSet in set (SortedSet is the implementation interface for TreeSet), and the inheritance between them is as follows:Java.util.Set;Java.util.SortedSet;Java.util.TreeSet;The elements in the SortedSet are unordered and cannot be duplicated,

In software systems, because IO is slower than memory, I/O reading and writing can become a bottleneck in many situations. Increasing the I/O speed has great benefits for improving the overall performance of the system.In Java's standard I/O, stream-