Java 将Iterable与列表进行比较会引发NullPointerException

我想将

Iterable

与

列表进行比较

我的方法是：

public Iterable<Class> findAll(final List<Long> idList) {
        final List<Class> result = new LinkedList<Class>();
        final List<List<Long>> partitions = ListUtils.partition(idList, 999);
        partitions.forEach(partition -> Iterables.addAll(result, this.repository.findAll(partition)));
        return result;
    }

当我将它们与
asserEquals（预期的，实际的）
进行比较时，我得到一个空点异常。
我知道它们有不同的类型，但它们有相同的值。为什么我不能比较它们？
我使用偶数.equals（）只是为了检查，但我仍然得到一个NPE

然后我试图得到第一个值

 assertEquals(expected.get(0), result.iterator().next());

我还是有一个NPE

我检查了Iterable文档，并编写了iterator（）抛出和NPE的代码

Iterator<T> iterator();

    /**
     * Performs the given action for each element of the {@code Iterable}
     * until all elements have been processed or the action throws an
     * exception.  Unless otherwise specified by the implementing class,
     * actions are performed in the order of iteration (if an iteration order
     * is specified).  Exceptions thrown by the action are relayed to the
     * caller.
     *
     * @implSpec
     * <p>The default implementation behaves as if:
     * <pre>{@code
     *     for (T t : this)
     *         action.accept(t);
     * }</pre>
     *
     * @param action The action to be performed for each element
     * @throws NullPointerException if the specified action is null
     * @since 1.8
     */

它们（其中一个）是空的吗？为什么要使用
Iterable
而不是
List
，这是这里常见的类型？@UlanMukhamedyanov不，它们不是空的。我猜您得到的是
actual
@dernor00返回的null。问题在于
类中的equals实现错误。如果需要更多帮助，请再次分享。可能您以错误的方式比较了两个空字段
Iterator<T> iterator();

    /**
     * Performs the given action for each element of the {@code Iterable}
     * until all elements have been processed or the action throws an
     * exception.  Unless otherwise specified by the implementing class,
     * actions are performed in the order of iteration (if an iteration order
     * is specified).  Exceptions thrown by the action are relayed to the
     * caller.
     *
     * @implSpec
     * <p>The default implementation behaves as if:
     * <pre>{@code
     *     for (T t : this)
     *         action.accept(t);
     * }</pre>
     *
     * @param action The action to be performed for each element
     * @throws NullPointerException if the specified action is null
     * @since 1.8
     */

java.lang.NullPointerException
    at ch.sbb.project.model.Class.equals(Class.java:224)
    at java.util.AbstractList.equals(AbstractList.java:523)
    at org.junit.Assert.isEquals(Assert.java:131)
    at org.junit.Assert.equalsRegardingNull(Assert.java:127)
    at org.junit.Assert.assertEquals(Assert.java:111)
    at org.junit.Assert.assertEquals(Assert.java:144)
    at ch.sbb.project.service.ServiceTest.findAll(ServiceTest.java:54)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)