Java Utililty Methods Collection Null

List of utility methods to do Collection Null

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Description

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

Method

intcountNonNull(Collection dist)
count Non Null 
int count = 0;
for (Double val : dist) {
    if (val != null) {
        count++;
return count;
intcountNotNull(Collection collection)
count Not Null 
int i = 0;
for (String item : collection) {
    if (item != null && !"!".equals(toKey(item))) {
        i++;
return i;
TgetItemAtPositionOrNull(Collection collection, int position)
Returns the n-th item or null if collection is smaller. 
if (position >= collection.size()) {
    return null;
if (collection instanceof List) {
    return ((List<T>) collection).get(position);
Iterator<T> iterator = collection.iterator();
T item = null;
...
intgetNextNullIndex(C collection)
get Next Null Index 
int output = -1;
int currentLoc = 0;
for (Object object : collection) {
    if (object == null) {
        output = currentLoc;
        break;
    currentLoc++;
...
intgetNumberOfNonNullElements(final Collection col)
get Number Of Non Null Elements 
if (col == null)
    return 0;
int result = 0;
for (final Object o : col) {
    if (o != null) {
        result++;
return result;
EgetSingleElementOrNull(Collection collection)
returns the one and only element of a collection or null if the collection is empty. 
if (collection.isEmpty()) {
    return null;
} else if (collection.size() > 1) {
    throw new IllegalStateException("collection has more than one elements");
} else {
    return collection.iterator().next();
intgetSizeNullSafe(final Collection collection)
Return the collection's size, or 0 if it is null 
return (collection == null) ? 0 : collection.size();
booleanhasAtLeastOneNotNullElement(Collection collection)
has At Least One Not Null Element 
if (collection == null)
    return false;
if (collection.isEmpty())
    return false;
if (collection.contains(null))
    return collection.size() > 1;
return collection.size() > 0;
booleanhasCollectionNullItem(Collection collection)
has Collection Null Item 
boolean hasNull = false;
Iterator iterator = collection.iterator();
while (iterator.hasNext() && !hasNull) {
    Object object = iterator.next();
    if (object == null) {
        hasNull = true;
return hasNull;
booleanisAllNull(Collection values)
is All Null 
boolean status = true;
for (String value : values) {
    if (value != null) {
        status = false;
        break;
return status;
...