Java Utililty Methods Reflection Generic Parameter

List of utility methods to do Reflection Generic Parameter

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Description

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

Method

Class[]getGeneric(ParameterizedType type)
get Generic 
try {
    if (type != null) {
        Type[] typeArgs = type.getActualTypeArguments();
        if (typeArgs != null && typeArgs.length > 0) {
            Class[] args = new Class[typeArgs.length];
            for (int i = 0; i < typeArgs.length; i++) {
                Type arg = typeArgs[i];
                args[i] = (Class) arg;
...
Type[]getGenericParameter(final Type type)
get Generic Parameter 
if (ParameterizedType.class.isInstance(type)) {
    return ParameterizedType.class.cast(type).getActualTypeArguments();
if (GenericArrayType.class.isInstance(type)) {
    return getGenericParameter(GenericArrayType.class.cast(type).getGenericComponentType());
return null;
TypegetGenericParameter(final Type type, final int index)
get Generic Parameter 
if (!(type instanceof ParameterizedType)) {
    return null;
final Type[] genericParameter = getGenericParameters(type);
if (genericParameter == null) {
    return null;
return genericParameter[index];
...
ListgetGenericParameterList(Type type)
get Generic Parameter List 
if (ParameterizedType.class.isInstance(type)) {
    final ParameterizedType paramType = ParameterizedType.class.cast(type);
    return Arrays.asList(paramType.getActualTypeArguments());
if (GenericArrayType.class.isInstance(type)) {
    final GenericArrayType arrayType = GenericArrayType.class.cast(type);
    return getGenericParameterList(arrayType.getGenericComponentType());
@SuppressWarnings("unchecked")
List<Type> emptyList = Collections.EMPTY_LIST;
return emptyList;
Type[]getGenericParameters(final Type type)
get Generic Parameters 
if (type instanceof ParameterizedType) {
    return ParameterizedType.class.cast(type).getActualTypeArguments();
if (type instanceof GenericArrayType) {
    return getGenericParameters(GenericArrayType.class.cast(type).getGenericComponentType());
return null;
TypegetGenericParameterType(Method method, int paramIdx)
get Generic Parameter Type 
return method.getGenericParameterTypes()[paramIdx];
TypegetGenericParameterType(Type type, int index)
get Generic Parameter Type 
if (!ParameterizedType.class.isInstance(type)) {
    return null;
final Type[] genericParameterTypeList = getGenericParameterTypes(type);
if (genericParameterTypeList.length == 0 || genericParameterTypeList.length < index) {
    return null;
return genericParameterTypeList[index];
...
Type[]getGenericParameterTypes(final Type type)
get Generic Parameter Types 
if (ParameterizedType.class.isInstance(type)) {
    return ParameterizedType.class.cast(type).getActualTypeArguments();
if (GenericArrayType.class.isInstance(type)) {
    return getGenericParameterTypes(GenericArrayType.class.cast(type).getGenericComponentType());
return EMPTY_TYPES;
Type[]getGenericParameterTypes(Method m)
get Generic Parameter Types 
return m.getGenericParameterTypes();
Type[]getGenericParameterTypes(Type t)
get Generic Parameter Types 
if (ParameterizedType.class.isInstance(t)) {
    ParameterizedType pt = ParameterizedType.class.cast(t);
    return pt.getActualTypeArguments();
} else
    return null;