core java online course

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

thread invokes the call method, and when the Get () method in the future is called, the thread is blocked until the call ends and the result is returned.Of the above 3 methods, the first two do not have a return value, only the last one with the return value. When multi-threading is required, it is recommended to implement the Runnable interface, mainly because: first, the thread class provides many ways for a derived class to invoke or override, and only the run () method must be overridden to

equals-1. Of course, it is not simple to change from the int type of-1 to the byte type of 1, but instead to the int type of a positive integer to truncate the Java virtual machine to the byte type of-1. So what is this positive integer? To tell the truth, I took the advanced calculator for a day and finally found it on Google: 2147483647. As long as the value of a in the above statement is changed to this

); - returnJint (HWND); in } - return 0; to } + return 0; -}Johness_jcef3_util_awtutilCompile Build　　　　 Use or test Copy the generated DLL into the Java project, configure LibraryPath in the project configuration, and write the test code.　　　　　　　　The test code is also simple: PackageJohness.jcef3.util;ImportJavax.swing.JFrame; Public classMain { Public Static voidMain (string[] args) {system.loadlibrary

thread is an object in Java, what are the properties of this object? Thread properties can be divided into static and dynamic properties, static here refers to the programmer is immutable, there is a JVM allocation, dynamic refers to the programmer can be customized, although the JVM gave the default property values. Static attributes: ID, etc., Dynamic properties: Name,priority,deamon,group,classloader, etc. So much for the basics, that's what it's

The problem of this blog cannot be solved. It is just an analysis and speculation. Some subsequent actions may prove some guesses and may not solve anything. If you have any questions in the same situation as me, please kindly advise. Problem: Last weekend, I went out to outing with my colleagues and managed my children at home. I went to the production environment and observed the current running status of the cluster machines. I found that the pressure on these multi-

getdeclarefields through the class objectThe key method for viewing object fields is the Get method in the field class. If f is an object of Type field, and obj is an object of a class that contains an F field, F.get (obj) returns an object whose value is the current value of the domain with the same name as F in the Obj field.Employee harry=New employee ("Harry hacker,35000,10,1,1989"); Class C1=harry.getclass (); Field F=c1.getdeclaredfield ("name"); Object v=f.get (Harry);The default behavio

There are several core objects in NiO that need to be mastered: buffer, channel, selector (Selector).Buffer buffersBuffer is actually a container object, more directly, is actually an array, in the NIO library, all the data are processed in buffer. When the data is read, it is read directly into the buffer, and it is written to the buffer when the data is written, and any time the data in the NIO is accessed, it is placed in the buffer. In a stream-or

online preview. Swffilepat is the path to the converted file.Note the problem:1, found that the error is generally OpenOffice service is not open.2, the Linux environment will exist in Chinese garbled problem, Linux is not like Windows support so many fonts, need to install many fonts, and the location of the font to link to the location of the flexpaper. In the use of pdf2swf plus parameter-s languagedir=/usr/local/xpdf-chinese-simplified/. Specific

time.Look directly at an example:public class program{static void Main (string[] args) { UI layer = new UI (); Layer. Setdataaccessor (New Xmldataaccessor ()); Layer. Do (); }} class ui{dataaccessor m_accessor; public void Setdataaccessor (Dataaccessor accessor) {m_accessor = accessor;} public void does () { m_accessor. GetUser (); }} interface dataaccessor{void GetUser (); void RegisterUser ();} class xmldataaccessor:dataaccessor{public void GetUser () {} public void RegisterUser () {}}Th

Today, we will introduce you to the full version of the JAVA online video tutorial. We know that Java is an object-oriented programming language that can write cross-platform applications, sun Microsystems launched the Java programming language and Java platform (JavaSE, Jav

establishment of i+1Analysis: Suppose i is of type int , when the value range (overflow) of type int is exceeded after i+1 , at this time i+1 will become negative, obviously negative positivethe data type of the 8.0.123 is (double)Analysis:0.123 Of course is double ,0.123f or 0.123F is Float9. Which of the following is the character-oriented output stream (A)A.bufferedwriterB.fileinputstreamC.objectinputstreamD.inputstreamreader Analysis:

/gravity/southeast7. Does the existence of I make The establishment of i+1Analysis: If i is of type int , when the value range (overflow) of type int is exceeded after i+1 . At this point the i+1 becomes negative, obviously negative positivethe data type of the 8.0.123 is (double)Analysis:0.123 is of course double . 0.123f or 0.123F is float9. Which of the following is a character-oriented output stream (A)A.bufferedwriterB.fileinputstreamC.objecti

IntroductionBefore using the online example of some of their own Java technology and the wheel of the fast "rotten" made some small applications, but after all, did not seriously understand and cognitive Java, it is intended to spend about one months time to savor ... Start from the beginning and go deeper!!Definition of JavaJava is not just a language, he is a c

Thread pool is a key point to be mastered in multi-threaded learning.The cost of starting a new thread is higher because it involves interacting with the operating system. In this scenario, using the thread pool can improve performance, especially if you need to consider using a thread pool when you want to create a lot of short-lived threads in your program.I. How do I create a thread pool??Before Java5, the thread pool was developed manually, and from Java5 onwards,

BTrace: Java online troubleshooting tool, btrace troubleshooting What is BTrace? BTrace is a killer for checking and solving online problems. BTrace can obtain all information during program execution by writing scripts. Note that you do not need to restart the service. Yes, you do not need to restart the service. Write the script and run it directly without the

Java core programming-byte stream of IO stream (2), javaio 1. byte stream A 1.1-byte stream is a stream that operates byte. Byte streams can operate on any data, such as media data, music, movies, and images. Of course, they can also operate on characters. Byte stream is based on byte stream, we know that a byte is 8 binary bits, a byte corresponds to an English

)throwsException {String identifier=Generatelicensekey (); SYSTEM.OUT.PRINTLN (identifier); }}Get JVM DataJVM data is an important set of parameters to monitor the application, the general local development can be connected to the corresponding process by jconsole to view the relevant metrics data, but the online environment is not suitable for viewing through the jconsole, so we now use Java code to obt

Recently has been studying fckeditor editors, online to find some information. One, File download 1): Fckeditor_2.6.4.zip (main file package, contains the main style CSS, templates, js file)Address: Http://nchc.dl.sourceforge.net/sourc...itor_2.6.4.zip2): Fckeditor-java-2.4.1-bin.zip (Java support package) address Http://nchc.dl.sourceforge.net/sourc...-2.4.1-bin

(four bytes are positive or negative, the first bit is the sign bit-231 ~ 231-1), when s[0]31n-1 + s[1]31n-2 + ... + s[n-1] It may overflow when it is large enough to cause it to become negative. From the above we can see that two different strings may be mapped to the same integer, and there is a conflict. So Java developers chose the multiplier factor of 31, and try to make the results of each string map evenly distributed throughout the entire