public int getClassIndex() {
		return classIndex & 0xffff;
	}
The value of the class_index item must be a valid index into the
constant_pool table. The constant_pool entry at that index must be a
CONSTANT_Class_info structure representing the innermost class that
encloses the declaration of the current class.
@return a valid index into the constant_pool table
Ghidra/Processors/JVM/src/main/java/ghidra/javaclass/format/attributes/EnclosingMethodAttribute.java