NoSuchFieldException on getClass().getField()

Question

java.lang.NoSuchFieldException: id

The below line is creating the exception.

String fieldValue =String.valueOf(studyplanCategory.getClass().getField(filterProperty).get(studyplanCategory)); 

studyplanCategory is a valid object and has got actual values. Beacuse of this exception the load method and the search function in the LazyLoading DataTable of my JSF webapp is not working.

Answer 1

From the Javadoc for Class.getField(...):

Returns a Field object that reflects the specified public member field of the class or interface represented by this Class object. The name parameter is a String specifying the simple name of the desired field. The field to be reflected is determined by the algorithm that follows. Let C be the class represented by this object:

If C declares a public field with the name specified, that is the field to be reflected. If no field was found in step 1 above, this algorithm is applied recursively to each direct superinterface of C. The direct superinterfaces are searched in the order they were declared. If no field was found in steps 1 and 2 above, and C has a superclass S, then this algorithm is invoked recursively upon S. If C has no superclass, then a NoSuchFieldException is thrown. See The Java Language Specification, sections 8.2 and 8.3.

If the field you are trying to retrieve via:

studyplanCategory.getClass().getField(filterProperty)

is private, then you will get a NoSuchFieldException. For private fields, try this instead:

studyplanCategory.getClass().getDeclaredField(filterProperty)

And to get around potential illegal access exceptions when setting values via a field this way:

Field field = studyplanCategory.getClass().getDeclaredField(filterProperty);
field.setAccessible(true);
field.get(studyplanCategory);