Question

我试图通过查看其二进制数据来了解如何确定 .class 文件的版本。我知道使用javap会告诉我版本 - 但遗憾的是我并不总是在需要检查的机器上安装 JDK 。但我可以访问普通的旧HEX编辑器......

我尝试从经过认证的来源找到相关文档 - 我能够提出的就是：http://fredericktang.wordpress.com/2007/09/28/java-class-file-version/
虽然这篇博文非常精彩 - 但它并没有真正备份官方Java文档。

任何提示？

编辑：没关系 - 抱歉 - 我找到了规范： here

Answer 1

您引用的文档实际上是JVM类文件规范的逐字转录（更易于使用英语）。

我保持方便的一些hitoric值

Major  Major(hex) Minor Java platform version 
45     2d          3           1.0
45     2d          3           1.1
46     2e          0           1.2
47     2f          0           1.3
48     30          0           1.4
49     31          0           1.5
50     32          0           1.6

---为响应Neil的观察而编辑，1.0和1.1使用相同的少数主要数字---

从类标题中，无法确定该类是否针对1.0或1.1版本的Java进行编译。也就是说，还有许多其他技术可以帮助确定是否针对1.0或1.1编译了一个类。

首先，如果该类是针对1.1编译的，那么它可能包含一个仅1.1的库类。一旦在其中一个类中找到其中一个，就可以安全地得出结论，它是针对Java 1.1编译的类。

请注意，可以在类的开头搜索常量池，以确定类文件需要哪些类才能完全解析所有外部引用。

单独搜索课程可能很麻烦，幸运的是还添加了很多软件包。以下包特定于Java 1.1，即它们未包含在Java 1.0

中

+ java.awt.datatransfer
+ java.awt.event
+ java.beans
+ java.lang.reflect
+ java.math
+ java.rmi.dgc
+ java.rmi
+ java.rmi.registry
+ java.rmi.server
+ java.security.acl
+ java.security
+ java.security.interfaces
+ java.sql
+ java.text
+ java.util.zip

在围栏的另一侧，对以下方法的大量调用建议（但不是实际证明）代码是针对Java 1.0编写的，因为它们在Java 1.1中由于新的awt事件重构而被弃用。

Deprecated Classes

java.io.LineNumberInputStream:
    LineNumberInputStream is deprecated. 
java.io.StringBufferInputStream:
    StringBufferInputStream is deprecated. 

Deprecated Methods

java.awt.BorderLayout:
    addLayoutComponent() is deprecated. 
java.awt.CardLayout:
    addLayoutComponent() is deprecated. 
java.awt.CheckboxGroup:
    getCurrent() is deprecated. 
java.awt.CheckboxGroup:
    setCurrent() is deprecated. 
java.awt.Choice:
    countItems() is deprecated. 
java.awt.Component:
    getPeer() is deprecated. 
java.awt.Component:
    enable() is deprecated. 
java.awt.Component:
    enable() is deprecated. 
java.awt.Component:
    disable() is deprecated. 
java.awt.Component:
    show() is deprecated. 
java.awt.Component:
    show() is deprecated. 
java.awt.Component:
    hide() is deprecated. 
java.awt.Component:
    location() is deprecated. 
java.awt.Component:
    move() is deprecated. 
java.awt.Component:
    size() is deprecated. 
java.awt.Component:
    resize() is deprecated. 
java.awt.Component:
    resize() is deprecated. 
java.awt.Component:
    bounds() is deprecated. 
java.awt.Component:
    reshape() is deprecated. 
java.awt.Component:
    preferredSize() is deprecated. 
java.awt.Component:
    minimumSize() is deprecated. 
java.awt.Component:
    layout() is deprecated. 
java.awt.Component:
    inside() is deprecated. 
java.awt.Component:
    locate() is deprecated. 
java.awt.Component:
    deliverEvent() is deprecated. 
java.awt.Component:
    postEvent() is deprecated. 
java.awt.Component:
    handleEvent() is deprecated. 
java.awt.Component:
    mouseDown() is deprecated. 
java.awt.Component:
    mouseDrag() is deprecated. 
java.awt.Component:
    mouseUp() is deprecated. 
java.awt.Component:
    mouseMove() is deprecated. 
java.awt.Component:
    mouseEnter() is deprecated. 
java.awt.Component:
    mouseExit() is deprecated. 
java.awt.Component:
    keyDown() is deprecated. 
java.awt.Component:
    keyUp() is deprecated. 
java.awt.Component:
    action() is deprecated. 
java.awt.Component:
    gotFocus() is deprecated. 
java.awt.Component:
    lostFocus() is deprecated. 
java.awt.Component:
    nextFocus() is deprecated. 
java.awt.Container:
    countComponents() is deprecated. 
java.awt.Container:
    insets() is deprecated. 
java.awt.Container:
    layout() is deprecated. 
java.awt.Container:
    preferredSize() is deprecated. 
java.awt.Container:
    minimumSize() is deprecated. 
java.awt.Container:
    deliverEvent() is deprecated. 
java.awt.Container:
    locate() is deprecated. 
java.awt.FontMetrics:
    getMaxDecent() is deprecated. 
java.awt.Frame:
    setCursor() is deprecated. 
java.awt.Frame:
    getCursorType() is deprecated. 
java.awt.Graphics:
    getClipRect() is deprecated. 
java.awt.List:
    countItems() is deprecated. 
java.awt.List:
    clear() is deprecated. 
java.awt.List:
    isSelected() is deprecated. 
java.awt.List:
    allowsMultipleSelections() is deprecated. 
java.awt.List:
    setMultipleSelections() is deprecated. 
java.awt.List:
    preferredSize() is deprecated. 
java.awt.List:
    preferredSize() is deprecated. 
java.awt.List:
    minimumSize() is deprecated. 
java.awt.List:
    minimumSize() is deprecated. 
java.awt.List:
    delItems() is deprecated. 
java.awt.Menu:
    countItems() is deprecated. 
java.awt.MenuBar:
    countMenus() is deprecated. 
java.awt.MenuComponent:
    getPeer() is deprecated. 
java.awt.MenuComponent:
    postEvent() is deprecated. 
java.awt.MenuContainer:
    postEvent() is deprecated. 
java.awt.MenuItem:
    enable() is deprecated. 
java.awt.MenuItem:
    enable() is deprecated. 
java.awt.MenuItem:
    disable() is deprecated. 
java.awt.Polygon:
    getBoundingBox() is deprecated. 
java.awt.Polygon:
    inside() is deprecated. 
java.awt.Rectangle:
    reshape() is deprecated. 
java.awt.Rectangle:
    move() is deprecated. 
java.awt.Rectangle:
    resize() is deprecated. 
java.awt.Rectangle:
    inside() is deprecated. 
java.awt.ScrollPane:
    layout() is deprecated. 
java.awt.Scrollbar:
    getVisible() is deprecated. 
java.awt.Scrollbar:
    setLineIncrement() is deprecated. 
java.awt.Scrollbar:
    getLineIncrement() is deprecated. 
java.awt.Scrollbar:
    setPageIncrement() is deprecated. 
java.awt.Scrollbar:
    getPageIncrement() is deprecated. 
java.awt.TextArea:
    insertText() is deprecated. 
java.awt.TextArea:
    appendText() is deprecated. 
java.awt.TextArea:
    replaceText() is deprecated. 
java.awt.TextArea:
    preferredSize() is deprecated. 
java.awt.TextArea:
    preferredSize() is deprecated. 
java.awt.TextArea:
    minimumSize() is deprecated. 
java.awt.TextArea:
    minimumSize() is deprecated. 
java.awt.TextField:
    setEchoCharacter() is deprecated. 
java.awt.TextField:
    preferredSize() is deprecated. 
java.awt.TextField:
    preferredSize() is deprecated. 
java.awt.TextField:
    minimumSize() is deprecated. 
java.awt.TextField:
    minimumSize() is deprecated. 
java.awt.Window:
    postEvent() is deprecated. 
java.io.ByteArrayOutputStream:
    toString() is deprecated. 
java.io.DataInputStream:
    readLine() is deprecated. 
java.io.PrintStream:
    PrintStream() is deprecated. 
java.io.PrintStream:
    PrintStream() is deprecated. 
java.io.StreamTokenizer:
    StreamTokenizer() is deprecated. 
java.lang.Character:
    isJavaLetter() is deprecated. 
java.lang.Character:
    isJavaLetterOrDigit() is deprecated. 
java.lang.Character:
    isSpace() is deprecated. 
java.lang.ClassLoader:
    defineClass() is deprecated. 
java.lang.Runtime:
    getLocalizedInputStream() is deprecated. 
java.lang.Runtime:
    getLocalizedOutputStream() is deprecated. 
java.lang.String:
    String() is deprecated. 
java.lang.String:
    String() is deprecated. 
java.lang.String:
    getBytes() is deprecated. 
java.lang.System:
    getenv() is deprecated. 
java.net.Socket:
    Socket() is deprecated. 
java.net.Socket:
    Socket() is deprecated. 
java.util.Date:
    Date() is deprecated. 
java.util.Date:
    Date() is deprecated. 
java.util.Date:
    Date() is deprecated. 
java.util.Date:
    Date() is deprecated. 
java.util.Date:
    UTC() is deprecated. 
java.util.Date:
    parse() is deprecated. 
java.util.Date:
    getYear() is deprecated. 
java.util.Date:
    setYear() is deprecated. 
java.util.Date:
    getMonth() is deprecated. 
java.util.Date:
    setMonth() is deprecated. 
java.util.Date:
    getDate() is deprecated. 
java.util.Date:
    setDate() is deprecated. 
java.util.Date:
    getDay() is deprecated. 
java.util.Date:
    getHours() is deprecated. 
java.util.Date:
    setHours() is deprecated. 
java.util.Date:
    getMinutes() is deprecated. 
java.util.Date:
    setMinutes() is deprecated. 
java.util.Date:
    getSeconds() is deprecated. 
java.util.Date:
    setSeconds() is deprecated. 
java.util.Date:
    toLocaleString() is deprecated. 
java.util.Date:
    toGMTString() is deprecated. 
java.util.Date:
    getTimezoneOffset() is deprecated.

可以证明Java代码是1.1版，但仅在某些情况下（如果代码使用新添加的1.1功能）。通常不可能证明Java代码是1.0，但是没有使用Java 1.1特性，并且大量使用Java不推荐使用的功能暗示了针对Java 1.0环境的类。

我不知道任何可能能够区分这两者的类内标记（行号表的差异等），主要是因为我没有必要在十六进制中挖掘1.0和1.1类编辑器。

Answer 2

JVM specification与您将获得的权威一样具有权威性。 Chapter 4可能就是你所追求的。

我如何知道编译了.class文件的Java版本？

2 个答案: