What are the common causes of NoSuchFieldException in Java?

What are the common causes of NoSuchFieldException in Java?

In Java programming, we often encounter NoSuchFieldException, which is a common exception type that usually indicates that a field that does not exist in the current class or its parent class is accessed. So, what are the causes of NoSuchFieldException exception? Below, we will conduct a detailed analysis.

1. Field name spelling error

When we access a field of a class, if the field name is spelled incorrectly, a NoSuchFieldException exception will be thrown. For example, if a field named username is defined, but we write it as usernam when accessing, this exception will be thrown.

2. The fields accessed are private properties

In Java, private properties of a class cannot be directly accessed. If we access through reflection, we also need to use setAccessible() Only when the method is set to true can it be accessed normally. If not set or set to false, a NoSuchFieldException will be thrown.

3. Field access in the inheritance relationship

In the Java inheritance relationship, if a class inherits multiple parent classes, then when accessing the fields of these parent classes, Pay special attention because these parent class fields may not be included in subclasses. If a field that does not exist is accessed, a NoSuchFieldException will be thrown.

4. The field exists but is invisible

In Java, sometimes we can access the public properties of a class, but we cannot access the private properties of the class. . This is because, even if the private property exists, we cannot directly access it due to its invisible nature, and a NoSuchFieldException will be thrown.

5. Field is deleted or hidden

In some cases, we define a field in a class, which may be deleted or hidden in later code. If the deleted or hidden field name is still used when accessing, a NoSuchFieldException will be thrown.

To sum up, there are many reasons for the NoSuchFieldException exception in Java. Special attention should be paid to the fact that this exception is sometimes covered up by other exceptions. Therefore, when a problem occurs, the exception information must be carefully analyzed to determine the real Exception types can find the root cause and solve the problem.

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