如何编译以Java 1.0为目标 [英] How to compile to target Java 1.0

问题描述

我想将代码编译为Java 1.0版.

I want to compile my code down to Java version 1.0.

我设法将其编译为1.1:

$ java -version
openjdk version "1.8.0_181"
OpenJDK Runtime Environment (build 1.8.0_181-8u181-b13-2~deb9u1-b13)
OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)
$ javac -target 1.2 -source 1.2 MyClass.java
(works with some warnings)
$ javac -target 1.1 -source 1.2 MyClass.java
(works with some warnings)

但是target选项似乎不接受1.0:

$ javac -target 1.0 -source 1.2 MyClass.java
javac: invalid target release: 1.0

我如何定位JDK 1.0?

How do I target JDK 1.0?

我希望我的 .class 和 .jar 文件能在尽可能多的系统上运行，包括非常老的系统，包括JDK 1.0. (我无权访问运行JDK 1.0的系统.)

I want my .class and .jar file to work as many systems as possible, including very old ones, including JDK 1.0. (I don't have access to a system running JDK 1.0.)

到目前为止我已经尝试过的:

What I've tried so far:

• 使用ecj-3.0.2.jar编译:不支持-target 1.0，最小值为-target 1.1.
• 使用JDK 1.0进行编译:我无法运行它，它尚未在Linux上发布.
• 使用JDK 1.1进行编译:我无法运行它，它尚未在Linux上发布.
• 使用JDK 1.2进行编译:Linux i386 javac二进制文件不起作用，这给了我分段错误.
• 使用JDK 1.3进行编译:javac: invalid target release: 1.0.
• 使用JDK 1.4进行编译:javac: invalid target release: 1.0.
• 使用JDK 1.5进行编译:javac: invalid target release: 1.0.这是第一个使用Linux amd64二进制文件的JDK.
• 使用JDK 1.6进行编译:javac: invalid target release: 1.0.
• 使用JDK 1.7进行编译:javac: invalid target release: 1.0.
• 使用JDK 1.8进行编译:javac: invalid target release: 1.0. (当我问这个问题时，我首先遇到了这个错误.)

• Compiling with ecj-3.0.2.jar: It doesn't support -target 1.0, the minimum is -target 1.1.
• Compiling with JDK 1.0: I couldn't run it, it wasn't released for Linux.
• Compiling with JDK 1.1: I couldn't run it, it wasn't released for Linux.
• Compiling with JDK 1.2: The Linux i386 javac binary doesn't work, it's giving me Segmentation fault.
• Compiling with JDK 1.3: javac: invalid target release: 1.0.
• Compiling with JDK 1.4: javac: invalid target release: 1.0.
• Compiling with JDK 1.5: javac: invalid target release: 1.0. This is the first JDK with Linux amd64 binaries.
• Compiling with JDK 1.6: javac: invalid target release: 1.0.
• Compiling with JDK 1.7: javac: invalid target release: 1.0.
• Compiling with JDK 1.8: javac: invalid target release: 1.0. (I got this error first, when I asked the question.)

我认为-target 1.0可以工作的原因是以下答案: https://stackoverflow.com/a/26148408

The reason why I believe that -target 1.0 may work is this answer: https://stackoverflow.com/a/26148408

推荐答案

TL; DR javac -target 1.1(并且不使用以后添加的任何类或方法)将使其在JDK上运行> = 1.0.2(于1995-09-16发行).回溯更多的想法是不可行的，因为较早的JDK尚未公开可供试用.

TL;DR javac -target 1.1 (and not using any classes or methods that were added later) will make it work on JDK >=1.0.2 (released on 1995-09-16). It's not feasible to go back more, because earlier JDKs are not publicly available to try.

javac -target ...标志值影响存储在.class文件中的次要版本号(字节偏移量4和5)和主版本号(字节偏移量6和7):

The javac -target ... flag value affects the minor (byte offset 4 and and 5) and major (byte offset 6 and 7) version number stored in the .class file:

JDK 1.8中的
• javac -target 1.1生成版本45.3，由JDK 1.0.2(1995年9月16日发布)，JDK 1.1.*(1997年2月发布)，JDK> = 1.2(1998-2003年发布)支持12). [源]
JDK 1.0.2中的
• javac(来自jdk-1_0_2-win32-x86.exe，在Linux上与wine一起运行)生成版本45.3.
• 对于k≥2，JDK版本1.k支持45.0到(44 + k).0(含)范围内的类文件格式版本. [源]
• javac -target 1.2生成版本46.0，受JDK> = 1.2.支持.
• javac -target 1.3生成版本47.0，受JDK> = 1.3.支持.
• javac -target 1.4生成版本48.0，受JDK> = 1.4的支持.
• 等

• javac -target 1.1 in JDK 1.8 generates version 45.3, supported by JDK 1.0.2 (released on 1995-09-16), JDK 1.1.* (released in 1997-02), JDK >=1.2 (released in 1998-12). [source]
• javac in JDK 1.0.2 (from jdk-1_0_2-win32-x86.exe, run with wine on Linux) generates version 45.3.
• For k ≥ 2, JDK release 1.k supports class file format versions in the range 45.0 through (44+k).0 inclusive. [source]
• javac -target 1.2 generates version 46.0, supported by JDK >=1.2.
• javac -target 1.3 generates version 47.0, supported by JDK >=1.3.
• javac -target 1.4 generates version 48.0, supported by JDK >=1.4.
• etc.

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