Java Utililty Methods List Concatenate

int size1 = l1.size();
if (size1 == 0) {
    return l2;
int size2 = l2.size();
if (size2 == 0) {
    return l1;
List<T> l3 = new ArrayList<T>(size1 + size2);
l3.addAll(l1);
l3.addAll(l2);
return l3;

List<T> ret = new ArrayList<>(list);
for (T item : items) {
    ret.add(item);
return ret;

StringBuilder sb = new StringBuilder();
for (String address : addresses) {
    sb.append(address).append(';');
sb.deleteCharAt(sb.length() - 1);
return sb.toString();

assert (empty.length == 0);
if (arrayList.iterator().hasNext() == false) {
    return empty;
int len = 0;
for (T[] subArray : arrayList) {
    len += subArray.length;
int pos = 0;
T[] result = Arrays.copyOf(empty, len);
for (T[] subArray : arrayList) {
    System.arraycopy(subArray, 0, result, pos, subArray.length);
    pos += subArray.length;
return result;

long[] result = new long[size];
int howManyLeft = size;
int targetPosition = 0;
int from = start;
for (int i = 0; i < arrays.size() && howManyLeft > 0; i++) {
    long[] current = arrays.get(i);
    int howManyThisRound = Math.min(current.length - from, howManyLeft);
    System.arraycopy(current, from, result, targetPosition, howManyThisRound);
...

List<T> newList = new ArrayList<T>();
for (T[] elArray : arrays) {
    newList.addAll(Arrays.asList(elArray));
return newList;

if (values == null || values.isEmpty())
    return null;
StringBuilder builder = new StringBuilder(escapeStringForCsvFormat(values.get(0), fieldSeparator));
for (int i = 1; i < values.size(); i++) {
    builder.append(fieldSeparator);
    builder.append(escapeStringForCsvFormat(values.get(i), fieldSeparator));
return builder.toString();
...

StringBuffer sb = new StringBuffer();
if (aliases.size() > 0) {
    sb.append(aliases.get(0));
    for (int i = 1; i < aliases.size(); i++) {
        sb.append(", "); 
        sb.append(aliases.get(i));
return sb.toString();

List<String> result = new ArrayList<String>();
int openBracketCounter = 0;
String currentElement = null;
for (String el : input) {
    openBracketCounter = openBracketCounter + getAmountOfCharInString('(', el)
            - getAmountOfCharInString(')', el);
    if (currentElement == null) {
        currentElement = el;
...

StringBuffer buffer = new StringBuffer();
Iterator i = aList.iterator();
if (i.hasNext()) {
    buffer.append(i.next());
    while (i.hasNext()) {
        buffer.append(' ');
        buffer.append(i.next());
return buffer.toString();