如何解决 java.lang.NullPointerException 错误? [英] How to solve java.lang.NullPointerException error?

问题描述

当我运行我的 Java 程序时，它在这一行给我一个错误

When I run my Java program, it gives me an error on this line

compiler.getTask(null, null, new DiagnosticCollector(), null, null, compilerUnits);

我得到的错误是:

Exception in thread "main" java.lang.NullPointerException
    at AnotherClassLoader.loadClass(test.java:58)
    at test.main(test.java:30)
    at Main.main(Main.java:68)

你能告诉我如何解决这个错误吗?

Can you please tell me how can I solve this error?

推荐答案

NullPointerException 意味着您传递的变量之一为 null，但代码尝试使用它，但实际上并非如此.

A NullPointerException means that one of the variables you are passing is null, but the code tries to use it like it is not.

例如，如果我这样做:

Integer myInteger = null;
int n = myInteger.intValue();

代码试图获取 myInteger 的 intValue，但由于它是 null，所以它没有:发生空指针异常.

The code tries to grab the intValue of myInteger, but since it is null, it does not have one: a null pointer exception happens.

这意味着您的 getTask 方法期望的不是空值，但您传递的是空值.弄清楚 getTask 需要什么并传递它想要的东西！

What this means is that your getTask method is expecting something that is not a null, but you are passing a null. Figure out what getTask needs and pass what it wants!

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