best java reference book

1. New operator. Dynamically (during runtime) allocates memory for the object and returns a reference to the object. The object reference is similar to the memory pointer. The main difference is that the object reference cannot be referenced as the actual pointer operation, and the object reference cannot be directed t

(intAint*b) {7 intt = *A;8* A = *b;9* B =T;Ten } One voidMain () { A intA =0, B =1; -printf"1:a =%d, B =%d\n", A, b); - Swapvalue (A, b); theprintf"2:a =%d, B =%d\n", A, b); -Swappointer (a, b); -printf"3:a =%d, B =%d\n", A, b); -}Operation Result: 1:a = 0, B = 1 2:a = 0, B = 1 3:a = 1, b = 0 As you can see clearly, passing parameters by pointer can easily modify the values passed in through the parameters, but not by value.In Java:Using a method like Swapvalue still c

Pass Value---Passing basic data type parameters Copy Code code as follows: public class passvalue{ static void Exchange (int a, int b) {//static methods, exchanging a,b values int temp; temp = A; A = b; b = temp; } public static void Main (string[] args) { int i = 10; int j = 100; System.out.println ("Before Call:" + "i=" + i + "T" + "J =" + j);/Before calling Exchange (I, j); Value passing, the main method can only invoke static methods System.out.println ("After call:" +

There are four types of references in java/android, namely:Strong reference-strong referencesSoft Reference-Soft referenceWeak Reference-Weak referencesPhantom Reference-Virtual referenceDifferent reference types have different ch

The main feature of soft reference (Soft Reference) is that it has strong reference function. This type of memory is recycled only when there is not enough memory, so they are usually not recycled when memory is sufficient. In addition, these reference objects are guaranteed to be set to NULL before

In jdk 1.2 and later versions, four concepts were introduced: strong reference, soft reference, weak reference, and virtual reference. There are a lot of explanations on these four concepts on the Internet, but most of them are general concepts. Today I have analyzed them with the Code. First, let's look at the definit

In the Java performance optimization series, memory management is a key factor of priority. When it comes to memory allocation, it will inevitably involve basic types and reference types. So today we will introduce the two types of their respective mysteries in terms of performance (for details about the other mysteries of the reference types, refer to "here ").

1. Saving in memory for basic types and reference typesData types in Java fall into two categories, basic types and object types. Accordingly, there are two types of variables: the base type and the reference type.A variable of the underlying type holds the original value, that is, the value it represents is the number itself, whereas a variable of the

Read a post on the internet to explain the value of Java and pass by reference, feel quite comprehensive, turn around, for later study reference:1: What is passed by valueRefers to when a method call passes a parameter that is passed by a copy of the value. Examples are as follows:public class Temptest {private void test1 (int a) { //do something} public static v

First, let's look at the following code:public class Test1 { String a = "123"; public static void change(Test1 test) { test.a="abc"; } public static void main(String[] args) { Test1 test1=new Test1(); System.out.println(test1.a); change(test1); System.out.println(test1.a); } }Results output 123 ABC believes that everyone can do the right thing for the problem. Java is passed by reference, and the value

What is the difference between a value type and a reference type in Java?CustomA reference type indicates that the data you are manipulating is the same, meaning that when you pass a parameter to another method, you change the value of the variable in another method,Then calling this method is the value of the passed variable will also change. A value type means

value to be stored, whose value represents the address pointed to. When you access a data with a reference type, you need to check the contents of the variable into the stack,The variable refers to an actual data in the heap. Data of a reference type data ratio type has greater storage size and lower access speed.There is a garbage collection mechanism in Java,

not: reference counting method and the algorithm of accessibility analysis . Reference Counting Method The logic of the reference counting method is very simple, but there is a problem, Java does not use this way to make object survival judgments. The logic of the reference

Prior to JDK1.2, references in Java were traditionally defined: if the value of the reference type represents the starting address of another piece of memory, it is called the memory represents a reference. This definition is pure, but too narrow, an object in this definition is only referenced or not referenced in two states, for how to describe a "tasteless, di

Recently went to interview, an interviewer asked about the parameters in the Java problem, I feel that this piece is not deep enough to understand. Today we will learn about interfaces and abstract classes in Java. The following is the directory outline for this article:One. What is passed by value and what is passed by referenceTwo. Whether parameter passing in Java