java video classes

(NewRunnable () {7 @Override8 Public voidrun () {9 Try {TenThread.Sleep (50); One}Catch(interruptedexception e) { A e.printstacktrace (); - } - for(inti = 0; I ) the System.out.println (str); - } - }). Start (); - +System.out.println ("Main thread finished"); - } +}① Line 4th defines a local variable str in the Main method, line 6th defines a local inner class thread, and accesses str in the local inner class

do not necessarily contain abstract methods, but classes that contain abstract methods must be declared as abstract classes. The abstract class itself does not have the actual functionality and can only be used to derive its subclasses. an abstract class can contain a constructor method, but a construction method cannot be declared abstract.Call the methods in the abstract class (abstract and non-abstract

:　　　　　　int n = 10;　　　　　　Integer a = new integer (n); int to Integer (boxing)Integer B = integer.valueof (n); int to Integer (boxing)int k = A.intvalue (); Integer to int (unboxing)2, integer internal common methodsint n = integer.parseint ("123"); The string is converted to int, and if the argument is not a numeric string, an exception numberformatexception occurs.int k = Integer.parseint ("123", 16); The parameter can be two, and the following represents the binary you want to convert to.　　　　　　

For Nested classes, see this article. For more information about internal classes, see this article. It is worth noting that Static internal classes cannot access external non-static members (restricted by the non-static member access conventions of Java static members) The internal class. Class file name

The relationship between classes (objects) 1, inheritance relationships C + + has multiple inheritance mechanisms. If you have a member variable of the same name in the two parent class of a class, it is more difficult to handle. 2. Realization relationship (class and Interface, polymorphic) 3, association relationship is the weakest relationship. An association relationship is an object in a class that has another class in its method. Life Example:

constructor for anonymous inner class test$1 contains two parameters, one is a reference to an external class object, and the other is an int variable, and it is clear that the parameter a in the variable test method is passed in as a argument to the copy of the anonymous inner class (copy of variable a) for assignment initialization.It is also said that if the value of a local variable can be determined during compilation, a copy is created directly inside of the anonymous interior. If the val

1. BigDecimal class overview:Since the float type and double are easy to lose precision when calculating. So in order to accurately express and calculate floating-point numbers, Java provides bigdecimal.BigDecimal: A signed decimal number that is immutable and arbitrarily accurate.2. BigDecimal Construction method1 Public BigDecimal (String val)3. use of BigDecimal (subtraction) 1 public BigDecimal Add (BigDecimal augend): Add 2 Public BigDe

static.Example of an internal class accessing an external classclass Outer {int num =3;class inner{int num =4;void Show () {int num = 5; SYSTEM.OUT.PRINTLN (num);//5system.out.println (This.num);//4system.out.println (Inner.this.num);// 4system.out.println (Outer.this.num);//3}}}class innerclass{public static void Main (String [] args) {Outer.Inner in =new Outer (). New Inner (); In.show ();}}Why does an inner class have direct access to members in an external class?Because the inner class hold

1, the difference between abstract class and interface:(1) An abstract class is a class that has only variables or method declarations, and these variables (attributes) and methods are abstract types. There is no implementation of the method for the abstract class.(2) An interface is a method declaration only. Without the implementation of a method, the method of an interface is also an abstract method, unlike an abstract class: an interface can only define static final member variables.2, abstr

dependency is that a method in a class can manipulate an instance of another class. In practical programming, it is recommended to minimize the number of interdependent classes. As shown in the following:Aggregation (HAS-A)Because the order needs to indicate what book to order, this involves the book class, that is, contains the book class. The difference between aggregation and dependency is that the order class can not have all the account class ob

. 245 page71 Video 8.6 Viewer mode for linkage Scenarios 8.4.3 page No. 25172 Video 8.7 Applying a dependency reversal principle can reduce the range of changes affected 8.5.1 No. 254 page73 Video 8.8 A single responsibility principle that can keep classes as stable as possible 8.5.2 No. 256 page74

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We know that when writing each class, we need to test whether the class has errors. by writing a main () method in each class, we have a disadvantage, that is, the additional code that has been compiled must be carried with it. If this is troublesome for you, you can use Nested classes to place the test code. /***** @ Author xiaanming **/public class innerclass {public void print (Object O) {system. out. println (O. tostring ();} public static class

(1) Introduction: An inner class is actually a type of local data that is defined within a class declaration. (very similar to the struct node declaration), which differs from Java. ----internal class declarations have public and private points If declared as public, it can also be used to define variables, such as Outer::inner var If the declaration is private, then the outside can not be used to define variables, then Outer::inner var will cause co

Basic Theory: ----------------------------------------------------- Java internal class: the definition of an internal class is defined within another class. The reason is: 1. An internal class object can access the implementation of the object created for it, including private data. That is, an internal class instance is privileged to the instance of the class that contains it. 2. for other classes

class, Java provides special syntax, and typically is initialized with a constructor method.For example:StringBuffer s = new StringBuffer ();This initializes the StringBuffer object as an empty object.If you need to create a StringBuffer object with content, you can use:StringBuffer s = new StringBuffer ("abc");The content of this initialized StringBuffer object is the string "abc".It is important to note that StringBuffer and string are of different