Java Brush title Diary 2018-08-01

The

1  Public classEqualsmethod2 {3      Public Static voidMain (string[] args)4     {5Integer N1 =NewInteger (47);6Integer N2 =NewInteger (47);7System.out.print (N1 = =n2);8System.out.print (",");9SYSTEM.OUT.PRINTLN (N1! =n2);Ten     } One}

Output Result:

False,true

Note: Use integer a = 1, or integer a = integer.valueof (1), or a value between 128 and 127 as the base type. Use integer a = new integer (1), regardless of the value, as the object. No.2

1 class   parent{2public           float  afun (floatfloat  b) {}}class  child  extends  parent{ 5
6}

It is not legal to insert any of the following methods into row 5. （ ）

A. float afun (float  A,  float  b) {}b.　　 publicint afun (intint  b) {}c.　　 publicfloat afun (float  p,  float  q) {}d.  privateint afun (int A,  int  b) {}

Answer: A

Note: Method overrides should follow the "three same small One big" principle: "Three identical": that is, the method name is the same, the formal parameter list is the same, the return value type is the same; "A small": a subclass method declaration throws an exception that is smaller or equal than the exception thrown by the parent method declaration; the access adornment of the subclass method Fu Chingbi The parent class method is larger or equal.

　　

No.3

For thread-local storage of TLS (thread local storage), the following statements are correct:

Answer: ABD
Note:

five basic principles of object-orientedSingle Responsibility principle (SRP)
Open Closure principle (OCP)
Richter Replacement principle (LSP)
dependency Inversion principle (DIP)
Interface Isolation principle (ISP)

Java Brush title Diary 2018-08-01