Java Utililty Methods Reflection Generic Type from Field

List of utility methods to do Reflection Generic Type from Field

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Description

The list of methods to do Reflection Generic Type from Field are organized into topic(s).

Method

ClassgetGenericArgument(Field field, int index)
get Generic Argument 
final Class entryType;
Type genericType = field.getGenericType();
if (genericType instanceof ParameterizedType) {
    Type[] typeArgs = ((ParameterizedType) genericType).getActualTypeArguments();
    if (typeArgs != null && typeArgs.length > index) {
        if (typeArgs[index] instanceof Class) {
            entryType = (Class) typeArgs[index];
        } else {
...
ClassgetGenericClass(Field f, int n)
get Generic Class 
Type genericFieldType = f.getGenericType();
if (genericFieldType instanceof ParameterizedType) {
    ParameterizedType aType = (ParameterizedType) genericFieldType;
    Type[] fieldArgTypes = aType.getActualTypeArguments();
    return (Class<?>) fieldArgTypes[n];
return null;
Class[]getGenericClasses(Field field)
get Generic Classes 
return getGenericClasses(field.getGenericType());
ClassgetGenericElementType(Field field)
Get the element type for a Collection if possible using the JDK 1.5 generics API or null if not possible. 
return getType(field, 0);
ClassgetGenericFieldClassType(Class clz, String propertyName)
get Generic Field Class Type 
Field field = clz.getDeclaredField(propertyName);
field.setAccessible(true);
ParameterizedType parameterizedType = (ParameterizedType) field.getGenericType();
Class<?> genericClass = (Class<?>) parameterizedType.getActualTypeArguments()[0];
return genericClass;
ClassgetGenericFieldType(Field field, boolean isAllowNull)
Returns the generic type parameter of a return value by a field. 
Type t = field.getGenericType();
Class result = getGenericType(t, 0);
if (!isAllowNull && result == null) {
    return Object.class;
return result;
TypegetGenericFieldType(Object target, String fieldName)
get Generic Field Type 
try {
    return getField(target, fieldName).getGenericType();
} catch (NoSuchFieldException e) {
    throw new RuntimeException(e);
ClassgetGenericFieldTypeFromPosition(Field field, int position)
get Generic Field Type From Position 
try {
    Type genericType = field.getGenericType();
    ParameterizedType type = (ParameterizedType) genericType;
    return (Class<?>) type.getActualTypeArguments()[position];
} catch (Exception e) {
    return null;
intgetGenericlyTypeCount(Field field)
get Genericly Type Count 
if (field.getGenericType() instanceof ParameterizedType) {
    ParameterizedType type = (ParameterizedType) field.getGenericType();
    return type.getActualTypeArguments().length;
return 0;
ClassgetGenericMultivalueType(final Field p)
Returns the generic class of multi-value objects. 
if (p.getType() instanceof Class<?>) {
    final Type genericType = p.getGenericType();
    if (genericType != null && genericType instanceof ParameterizedType) {
        final ParameterizedType pt = (ParameterizedType) genericType;
        if (pt.getActualTypeArguments() != null && pt.getActualTypeArguments().length > 0) {
            if (((Class<?>) pt.getRawType()).isAssignableFrom(Map.class)) {
                if (pt.getActualTypeArguments()[1] instanceof Class<?>) {
                    return (Class<?>) pt.getActualTypeArguments()[1];
...