本文介绍了Java编译器API NullPointerException的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我使用这个代码在运行时编译一个Java文件。首先,这是我的目录树(在Eclipse中)。
I am using this code to compile a Java file at runtime. First of all, here is my directory tree (in Eclipse).
+---- src
+----- package
+------ Compile.java
+
+
+---- temp
+----- anotherpackage
+------ Temp.java (file to compile)
我的代码中我得到NullPointerException(我已经尝试使用JDK作为我的标准VM在Eclipse中)。
Here is my code where I am getting the NullPointerException (I already tried using JDK as my Standard VM in Eclipse).
public static void compile(URI path, InputStream is, OutputStream os, OutputStream err) throws IOException {
SimpleJavaFileObject source = new CustomJavaFileObject(path, Kind.SOURCE);
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
JavaCompiler.CompilationTask task = compiler.getTask(new PrintWriter(err), null, null, null, null, Arrays.asList(source));
task.call();
}
这里是CustonJavaFileObject:
Here is the CustonJavaFileObject:
class CustomJavaFileObject extends SimpleJavaFileObject {
protected CustomJavaFileObject(URI uri, Kind kind) {
super(uri, kind);
}
}
我做错了什么?
EDIT:
我在我的PATH中没有JDK it)
I do not have the JDK in my PATH (and I can't add it)
这是我的堆栈跟踪:
java.lang.NullPointerException
at package.Compiler.compile(Compiler.java:20)
at package.Interactive.main(Interactive.java:19)
推荐答案
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
会导致问题。指向你的JRE在JDK内部,与jdk不同,jre不提供任何工具。
causes the issue. Point your JRE to be inside the JDK as unlike jdk, jre does not provide any tools.
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