JDK1.1能支持版本号为45.0~45.65535的Class文件,JDK1.2则能支持45.0~46.65535的Class文件。JDK1.7可生成的Class文件主版本号的最大值为51.0。 3.常量池 紧接着魔数与版本号之后的是常量池入口,常量池是Class文件结构中与其它项目关联最多的数据类型,也是占用Class文件空间最大的数据项目之一,同时它还是在文件中第一个...
如下定义Simple类,使用javac -g:none Simple.java 编译出Simple.class 文件,并使用javap -v Simple > Simple.txt 查看反编译的信息,然后看Simple.class文件中的方法表集合是怎样组织的: packagecom.louis.jvm;publicclassSimple{publicstaticsynchronizedfinalvoidgreeting(){inta=10; } } 1. Simple.class文件组织信...
3、可以使用wrapper class的对象方法,进行各种值与基本数据类型的相互转换,如String类型的相互转换,还可以与各种进制的数据进行相互装换(二进制binary、八进制octal、十进制decimal、十六进制hexadecimal) 1. 1. 下表列出了各个wrapper class都具有的方法(Number 类的方法) 1. Methods Implemented by all Subclasses of...
public class Parent { public Object toObject(Number number) { return number.toString();} } 类Parent有一个方法toObject。我们声明一个子类继承这个类并尝试覆盖toObject方法转化Number为String。public class Child extends Parent { @Override public String toObject(Number number) { return number.toString()...
The abstract class Number is the superclass of platform classes representing numeric values that are convertible to the primitive types byte, double, float, int, long, and short.
out.format(fmt, "Number of declared constructors", allDeclConst.length); for (Constructor currentDeclConst : allDeclConst) { printConstructor(currentDeclConst); } } public static void printClassMethods(Class c) { Method[] allMethods = c.getDeclaredMethods(); ...
Methods: Any methods in the class Attributes: Any attributes of the class (for example the name of the sourcefile, etc) ClassFile表中各项简介如下: (1) magic(魔数) 每个Java class文件的钱四个字节被称为他的魔数(magic number):0xCAFEBABE。魔数的做作用在于。可以轻松的分辨出Java class文件和非Jav...
To use constants defined by the class, such asMIN_VALUEandMAX_VALUE, that provide the upper and lower bounds of the data type. To use class methods for converting values to and from other primitive types, for converting to and from strings, and for converting between number systems (decimal...
public class A { public void foo(String name) { System.out.println("Hello, " + name); } } 可以编写另外一个类来反射调用A上的方法: import java.lang.reflect.Method; public class TestClassLoad { public static void main(String[] args) throws Exception { ...
TheIntegerclass wraps a value of the primitive typeintin an object. It contains constants and methods useful when dealing with anint. Main.java void main() { int a = 55; Integer b = Integer.valueOf(a); int c = b.intValue(); ...