Java Utililty Methods Collection Combine

List of utility methods to do Collection Combine

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Description

The list of methods to do Collection Combine are organized into topic(s).

Method

Listcombine(Collection first, Collection second)
combine 
List<T> result = new ArrayList<T>(first.size() + second.size());
result.addAll(first);
result.addAll(second);
return result;
Listcombine(Collection... collections)
combine all lists into one list containing all elements. 
List<T> list = new ArrayList<T>();
if (collections != null && collections.length > 0) {
    for (Collection<?> c : collections) {
        for (Object t : c) {
            list.add((T) t);
return list;
Stringcombine(Collection strings)
combine 
Iterator<String> iter = strings.iterator();
if (!iter.hasNext()) {
    return "";
String rtrn = iter.next();
while (iter.hasNext()) {
    rtrn += "_" + iter.next();
return rtrn;
Collection>combine(final Collection[] c)
Functions that makes every possible combination of items from an array of collection while respecting the order of the collections. 
Collection<List<V>> result = new Vector();
Vector<V> combination = new Vector(c.length);
Iterator<V>[] state = new Iterator[c.length];
for (int i = 0; i < c.length; i++) {
    state[i] = c[i].iterator();
    if (state[i].hasNext())
        combination.add(state[i].next());
    else
...
Stringcombine(String separator, Collection parts)
combine 
return join(separator, parts);
Stringcombine(String separator, Collection stringCollection)
Combines a collection of strings into a single string, separated by the given character set 
return combineArray(separator, stringCollection.toArray(EMPTY_STRING_ARRAY));
Stringcombine(String separator, Collection objs)
Combine the objects in Collection with the specified separator. 
StringBuffer sb = new StringBuffer();
if (objs != null && objs.size() > 0) {
    Iterator<T> it = objs.iterator();
    for (;;) {
        sb.append(it.next().toString());
        if (it.hasNext())
            sb.append(separator);
        else
...
CollectioncombineAndRemoveDuplicates(Collection collection1, Collection collection2)
combine And Remove Duplicates 
Collection<T> merged;
try {
    merged = collection1.getClass().newInstance();
} catch (Exception ex) {
    merged = new ArrayList<T>();
merged.addAll(collection1);
merged.addAll(collection2);
...
CollectioncombineCollections(Collection sessionCollection, Collection reqCollection)
combine Collections 
Collection<T> result = null;
if (sessionCollection != null && !sessionCollection.isEmpty()) {
    result = new ArrayList<T>();
    result.addAll(sessionCollection);
if (reqCollection != null && !reqCollection.isEmpty()) {
    if (result == null) {
        result = new ArrayList<T>();
...
ListCombineCollections(final Collection... collections)
Used when you have two or more lists of units, etc and you want all the units in one collection. 
final List result = new ArrayList();
for (final Collection collection : collections) {
    result.addAll(collection);
return result;