Lesson1 Foundations of java and oo programming
Today , i take the first lesson of java ,let me sum up the details:
firstly,about jdk and jre.jdk stands for java development kit,while jre represent java Runtime Environment. jdk is the key of Java. And,jvm(java virtual machine) is the key of jre.
then ,about the platform independence of java.During the runing process of the java process,we should firstly compile the *.java source process,and generate the *. class file,and then bytecode,then run it by the jvm.This process make java be platform independence.
finally,the first java program----hello world
public class Hello{
public static void main(String args[]){
String str = "hello world!";
System.out.println("\"hello world!\"\t" + "+\t" + str);
}
};
then i look up sth about the bytecode,the information is below:
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