Cause: the class org.apache.tools.ant.taskdefs.optional.ANTLR was not found.

　　具体错误：

gluegen.build.javase:
 
generate.java:
 
BUILD FAILED
/home/tsit/jogamp232-loongarch64/gluegen/make/build.xml:957: The following error occurred while executing this line:
/home/tsit/jogamp232-loongarch64/gluegen/make/build.xml:694: The following error occurred while executing this line:
/home/tsit/jogamp232-loongarch64/gluegen/make/build.xml:653: Problem: failed to create task or type antlr
Cause: the class org.apache.tools.ant.taskdefs.optional.ANTLR was not found.
        This looks like one of Ant's optional components.
Action: Check that the appropriate optional JAR exists in
        -/home/tsit/apache-ant-1.10.11/dist/lib
        -/home/tsit/.ant/lib
        -a directory added on the command line with the -lib argument
Do not panic, this is a common problem.
The commonest cause is a missing JAR.
This is not a bug; it is a configuration problem      

 　什么意思？就是ant缺少东西。原因是吾自己下载编译了ant（因为到目前为止，loongarch64平台没有ant可更新安装），实际上lib的内容不对。解决办法：

• 下载ant

https://downloads.apache.org/ant/binaries/ https://ant.apache.org/bindownload.cgi

• 将其中的lib目录提出来覆盖ant的lib目录。