Java Utililty Methods Array Join

int[] result = new int[a.length + b.length];
System.arraycopy(a, 0, result, 0, a.length);
System.arraycopy(b, 0, result, a.length, b.length);
return result;

if (arr == null || arr.length == 0)
    return null;
if (joinStr == null)
    joinStr = "";
StringBuffer buf = new StringBuffer();
for (String str : arr)
    buf.append(str).append(joinStr);
return buf.substring(0, buf.length() - joinStr.length());
...

if (array == null || array.length == 0) {
    return "";
int len = array.length;
StringBuilder sb = new StringBuilder(16 + len * 8);
sb.append(array[0]);
for (int i = 1; i < len; i++) {
    sb.append(with);
...

StringBuffer sb = new StringBuffer();
boolean first = true;
for (Object o : array) {
    if (first)
        first = false;
    else
        sb.append(delim);
    sb.append(o.toString());
...

int len = 0;
for (byte[] b : bs) {
    len += b.length;
byte[] out = new byte[len];
int offset = 0;
for (byte[] b : bs) {
    System.arraycopy(b, 0, out, offset, b.length);
...

return join(sep, Arrays.asList(array));

StringBuilder sb = new StringBuilder();
boolean first = true;
for (String s : strings) {
    if (first) {
        first = false;
    } else {
        sb.append(separator);
    sb.append(s);
return sb.toString();

StringBuilder result = new StringBuilder();
for (CharSequence string : strings) {
    if (result.length() > 0) {
        result.append(separator);
    result.append(string);
return result.toString();
...

return join(array, ", ");

if (array == null) {
    return null;
return join(array, separator, 0, array.length);