CODEWITHSUNDEEP
javaandroid
Helen Cui
Helen Cui

Reputation: 191

java.lang.NoSuchMethodError: android.util.ArrayMap.put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;

I encountered a weird bug while doing JUnit test.

I'm using reflection to call a method I defined: MyReflectUtil.callMethod(testManager, "loadPermission"); Within the testManager there is an instance of ArrayMap. And loadPermission would call get() and put() on that instance.

This is the ArrayMap I defined:

public class ArrayMap<K, V> {
    HashMap<K, V> map = new HashMap<>();

    public void put(K key, V value) {
        map.put(key, value);
    }

    public V get(K key) {
        return map.get(key);
    }
}

Within the method loadPermission, I can call get() method, but when I call put() , I get the error:

java.lang.NoSuchMethodError: android.util.ArrayMap.put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;

What is this Ljava/lang/Object? When I log myArrayMapInstance.getClass().getDeclaredMethods(), I get:

public java.lang.Object android.util.ArrayMap.get(java.lang.Object), public void android.util.ArrayMap.put(java.lang.Object,java.lang.Object)

It does not have the letter L in front of java.lang.Object. Yet I can not explain why I can call get(), because it is fundamentally the same as put().

Can anyone help? Really appreciate it!

Upvotes: 0

Views: 117

Answers (1)

Forketyfork
Forketyfork

Reputation: 7810

The Ljava/lang/Object; after the closing bracket is the expected method's return type:

java.lang.NoSuchMethodError: android.util.ArrayMap.put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;

Your call expects a method that returns something, but in your ArrayMap code, this put method is void.

Upvotes: 1

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