Java Utililty Methods Collection to Array

List of utility methods to do Collection to Array

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Description

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

Method

Class[]toClassArray(Collection> collection)
to Class Array 
return collection == null ? null : collection.toArray(new Class[collection.size()]);
Class[]toClassArray(final Collection collection)
Convert the collection of class types to an array of class types. 
return (Class[]) collection.toArray(new Class[collection.size()]);
Double[]toDouble(final Collection numbers)
to Double 
return toDouble(numbers.toArray(new Number[numbers.size()]));
double[]toDoubleArray(Collection items)
Convert a Collection of Numbers to an array of primitive doubles Null values will be skipped in the array 
double ret[] = new double[items.size()];
int idx = 0;
for (Number n : items) {
    if (n != null)
        ret[idx] = n.doubleValue();
    idx += 1;
return (ret);
...
double[]toDoubleArray(Collection ds)
to Double Array 
double[] out = new double[ds.size()];
int index = 0;
for (Double d : ds)
    out[index++] = d;
return out;
Double[]toDoubleArray(final Collection doubleColl)
Converts the given collection of Doubles to an array of Doubles. 
if (doubleColl == null) {
    return new Double[0];
return doubleColl.toArray(new Double[doubleColl.size()]);
ObjecttoFloatArray(Collection collection)
to Float Array 
return toFloatArray(new float[collection.size()], collection);
float[]toFloatArray(Collection c)
to Float Array 
float arr[] = new float[c.size()];
int i = 0;
for (Number item : c) {
    arr[i++] = item.floatValue();
return arr;
float[]toFloatArray(Collection array)
to Float Array 
float[] resultArray = new float[array.size()];
int i = 0;
for (float s : array) {
    resultArray[i++] = s;
return resultArray;
float[]toFloatArray(final Collection c)
to Float Array 
if (null == c || c.isEmpty()) {
    return new float[0];
final float[] list = new float[c.size()];
int i = 0;
for (final Number item : c) {
    list[i] = item.floatValue();
    i++;
...