Class, abstract class, interface, inheritance and object (Java)
Zookeeper --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------This is not a teaching material. I sometimes look at it on th
included in the scope of the peripheral class.
Java has another internal class function, making the nested class of the internal analogy C ++ more useful. The internal class object has an implicit reference, which references the
The syntax for the "class name. This" is called "qualified this" in the Java language. The relevant provisions are here: Chapter 15. Expressions-qualified thisThe main purpose of this syntax is to use the outer class name. This syntax when you want to specify the "this" reference for a perimeter class of a
A. class file
Note: Each class file corresponds to a unique class or interface definition information, but the class or interface is not necessarily defined in a file (for example, a class or interface can also be generat
Java programming ideology note (6)-internal class, java programming ideology
1. DefinitionA class is defined inside another class. This class is called an internal class.
2. Link to the
example com.example.Sample , generates a byte code file after compilation Sample.class . Two different ClassLoader ClassLoaderA and ClassLoaderB read the Sample.class file separately, and define an java.lang.Class instance of two classes to represent the class. These two instances are not the same. For Java virtual machines, they are different classes. Attemptin
program is fully compiled on the local computer, the default ClassLoader is generallyVery well done. But one of the most exciting parts of Java is that it's easy to load classes from the Web rather than just the locals.For example, a browser can load a class from a custom class loader. And alsoMany ways to load classe
list of method names, and so on, which is the basis of reflection. 2. Essence AnalysisAs a simple example to explain: the name of a person is human, then the Java class name is class.If we instantiate a person, then its instantiation object is Zhang San or John Doe, and so on, class
, it is not possible to lose this static internal class. For example, during code program testing, if you set a primary method in each Java source file (the primary method is the entry to an application, which must be included ), there will be a lot of additional code. In addition, the code of this main program is only a form for
recursively processed.
Both the configuration (manifest) file name and the archive file name must be specified, in the same order specified by the 'M' and 'F' signs.
First, write a configuration file example. mf in the current directory of the resource file.
For a simple example, see: http://blog.csdn.net/studyvcmfc/article/details/7745500
Iii. java [actual ru
machine, run System program, use close hook1.1 Accessing System PropertiesFor example, get the operating system name Os.name, operating system version os.version, JVM name Java.vm.name, JDK version java.version, and so on. The System Properties collection is shown in table 1-1Table 1-1 system Property key values
Java.version
Java Runtime Environment version
Java.vendor
member methods, member variables, classes, and interfaces in the class with direct references, and before that, it is necessary to detect whether the referenced type correctness and access properties are correct (that is, public, private), such as checking that the final class is not inherited , check the correctness of static variables, and so on. (Note that there is actually a part of the validation proc
This article mainly introduces the Java language class class usage and generalization (detailed), we all know that Java program in the running process, all the object type identification, that is, Rtti. This information records the class to which each object belongs. A virtu
pool. The following are the most popular formats for the field table:
Type
Name
Number
U2
Access_flags
1
U2
Name_index
1
U2
Description_index
1
U2
Attributes_count
1
Attribute_info
Attributes
Attributes_count
The access_flags is very similar to the access_flags in the class and is a modifier that rep
From: http://klcwt.iteye.com/blog/452834
Create another class in a class called the internal class of the member. The internal class of this Member can be static (modified using the static keyword) or non-static. Static internal classes have various restrictions during definition and use. Therefore, it is not much use
); You can access the private member of the Inner class System.out.println (person.x);//The external class accesses the static members of the inner class: inner class. Static members System.out.println (Person.mail);//access to the public member of the Inner class} pub
transformed into a local internal class with a name, so that it can have constructors. Use the initialization code block in this anonymous internal class.
Many people may not be familiar with the inner class mentioned in Java. In fact, similar concepts also exist in C ++, that is,
, then will study this function extracts, defines a named person's abstract class.The person class only provides methods, and the specific implementation is by subclasses.Abstract class Person {abstract void study ();p ublic Void Show () {System.out.println ("person.show ()");} abstract void Dislay ();} Class Student extends person{public void study () {System.ou
Was has provided a powerful and flexible class loading mechanism since Version 6.1, but it also brings complexity in use. It may have been a normal project running on v6.0, the classnotfound problem occurs after being transplanted to v6.1. Here is an example.
After a project is migrated from v6.0 to v6.1,
1. If you use the normal deployment method, the system always reports that the
1. Design pattern: A problem-solving idea. The most effective way to solve a certain kind of problem. Java has 23 design patterns (summed up by predecessors).
Single-Example design pattern: Resolves a class that has only one object in memory.
if a class can always create only one instance, the
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