spring - Initial data on JPA repositories -

i'm looking convenient way provide initial data application. i've implemented spring data jpa based project foundation of database related operation.

example:

i've got entity role can assigned entity user. on clean application start provide directly default roles (e.g. admin, manager, etc).

best

i built random data factory :

public class randomdatafactory {      private static final string ungenerated_value_marker = "ungenerated_value_marker";      private static void randomlypopulatefields(object object) {         new randomvaluefieldpopulator().populate(object);     }      /**      * instantiates single object random data      */     public static <t> t getsingle(class<t> clazz) throws illegalaccessexception, instantiationexception {         t object = clazz.newinstance();         randomlypopulatefields(object);         return object;     }      /**      * returns unmodifiable list of specified type objects random data      *      * @param clazz     mypojo.class instantiated random data      * @param maxlength length of list returned      */     public static <t> list<t> getlist(class<t> clazz, int maxlength) throws illegalaccessexception, instantiationexception {         list<t> list = new arraylist<t>(maxlength);         (int = 0; < maxlength; i++) {             t object = clazz.newinstance();             randomlypopulatefields(object);             list.add(i, object);         }         return collections.unmodifiablelist(list);     }      /**      * returns unmodifiable list of specified type t objects random data      * <p>list length 3</p>      *      * @param clazz mypojo.class instantiated random data      */     public static <t> list<t> getlist(class<t> clazz) throws instantiationexception, illegalaccessexception {         return getlist(clazz, 3);     }      public static <t> t getprimitive(class<t> clazz) {         return (t) randomvaluefieldpopulator.generaterandomvalue(clazz);     }      public static <t> list<t> getprimitivelist(class<t> clazz) {         return getprimitivelist(clazz, 3);     }      public static <t> list<t> getprimitivelist(class<t> clazz, int length) {         list<t> randoms = new arraylist<t>(length);         (int = 0; < length; i++) {             randoms.add(getprimitive(clazz));         }         return randoms;     }      private static class randomvaluefieldpopulator {         public static object generaterandomvalue(class<?> fieldtype) {             random random = new random();               if (fieldtype.equals(string.class)) {                 return uuid.randomuuid().tostring();             } else if (date.class.isassignablefrom(fieldtype)) {                 return new date(system.currenttimemillis() - random.nextint());             } else if (localdate.class.isassignablefrom(fieldtype)) {                 date date = new date(system.currenttimemillis() - random.nextint());                 return new localdate(date);             } else if (fieldtype.equals(character.class) || fieldtype.equals(character.type)) {                 return (char) (random.nextint(26) + 'a');             } else if (fieldtype.equals(integer.type) || fieldtype.equals(integer.class)) {                 return random.nextint();             } else if (fieldtype.equals(short.type) || fieldtype.equals(short.class)) {                 return (short) random.nextint();             } else if (fieldtype.equals(long.type) || fieldtype.equals(long.class)) {                 return random.nextlong();             } else if (fieldtype.equals(float.type) || fieldtype.equals(float.class)) {                 return random.nextfloat();             } else if (fieldtype.equals(double.type)) {                 return random.nextint(); //if double used, jsonpath uses bigdecimal convert             } else if (fieldtype.equals(double.class)) {                 return random.nextdouble(); //if double used, jsonpath uses bigdecimal convert             } else if (fieldtype.equals(boolean.type) || fieldtype.equals(boolean.class)) {                 return random.nextboolean();             } else if (fieldtype.equals(bigdecimal.class)) {                 return new bigdecimal(random.nextfloat());             } else if (enum.class.isassignablefrom(fieldtype)) {                 object[] enumvalues = fieldtype.getenumconstants();                 return enumvalues[random.nextint(enumvalues.length)];             } else if (number.class.isassignablefrom(fieldtype)) {                 return random.nextint(byte.max_value) + 1;             } else {                 return ungenerated_value_marker;             }          public void populate(object object) {             reflectionutils.dowithfields(object.getclass(), new randomvaluefieldsettercallback(object));         }          private static class randomvaluefieldsettercallback implements reflectionutils.fieldcallback {             private final object targetobject;              public randomvaluefieldsettercallback(object targetobject) {                 this.targetobject = targetobject;             }              @override             public void dowith(field field) throws illegalaccessexception {                 class<?> fieldtype = field.gettype();                 if (!modifier.isfinal(field.getmodifiers())) {                     object value = generaterandomvalue(fieldtype);                     if (!value.equals(ungenerated_value_marker)) {                         reflectionutils.makeaccessible(field);                         field.set(targetobject, value);                     }                 }             }         }     } }