Here you can find the source of toPrimitive(Long[] array)
public static long[] toPrimitive(Long[] array)
//package com.java2s; //License from project: Apache License public class Main { public static final long[] EMPTY_LONG_ARRAY = new long[0]; public static final int[] EMPTY_INT_ARRAY = new int[0]; public static final short[] EMPTY_SHORT_ARRAY = new short[0]; public static final byte[] EMPTY_BYTE_ARRAY = new byte[0]; public static final double[] EMPTY_DOUBLE_ARRAY = new double[0]; public static final float[] EMPTY_FLOAT_ARRAY = new float[0]; public static final boolean[] EMPTY_BOOLEAN_ARRAY = new boolean[0]; public static long[] toPrimitive(Long[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_LONG_ARRAY; }/*from w w w. j a v a 2 s. c o m*/ final long[] result = new long[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].longValue(); } return result; } public static long[] toPrimitive(Long[] array, long valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_LONG_ARRAY; } final long[] result = new long[array.length]; for (int i = 0; i < array.length; i++) { Long b = array[i]; result[i] = (b == null ? valueForNull : b.longValue()); } return result; } public static int[] toPrimitive(Integer[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_INT_ARRAY; } final int[] result = new int[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].intValue(); } return result; } public static int[] toPrimitive(Integer[] array, int valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_INT_ARRAY; } final int[] result = new int[array.length]; for (int i = 0; i < array.length; i++) { Integer b = array[i]; result[i] = (b == null ? valueForNull : b.intValue()); } return result; } public static short[] toPrimitive(Short[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_SHORT_ARRAY; } final short[] result = new short[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].shortValue(); } return result; } public static short[] toPrimitive(Short[] array, short valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_SHORT_ARRAY; } final short[] result = new short[array.length]; for (int i = 0; i < array.length; i++) { Short b = array[i]; result[i] = (b == null ? valueForNull : b.shortValue()); } return result; } public static byte[] toPrimitive(Byte[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_BYTE_ARRAY; } final byte[] result = new byte[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].byteValue(); } return result; } public static byte[] toPrimitive(Byte[] array, byte valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_BYTE_ARRAY; } final byte[] result = new byte[array.length]; for (int i = 0; i < array.length; i++) { Byte b = array[i]; result[i] = (b == null ? valueForNull : b.byteValue()); } return result; } public static double[] toPrimitive(Double[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_DOUBLE_ARRAY; } final double[] result = new double[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].doubleValue(); } return result; } public static double[] toPrimitive(Double[] array, double valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_DOUBLE_ARRAY; } final double[] result = new double[array.length]; for (int i = 0; i < array.length; i++) { Double b = array[i]; result[i] = (b == null ? valueForNull : b.doubleValue()); } return result; } public static float[] toPrimitive(Float[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_FLOAT_ARRAY; } final float[] result = new float[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].floatValue(); } return result; } public static float[] toPrimitive(Float[] array, float valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_FLOAT_ARRAY; } final float[] result = new float[array.length]; for (int i = 0; i < array.length; i++) { Float b = array[i]; result[i] = (b == null ? valueForNull : b.floatValue()); } return result; } public static boolean[] toPrimitive(Boolean[] array) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_BOOLEAN_ARRAY; } final boolean[] result = new boolean[array.length]; for (int i = 0; i < array.length; i++) { result[i] = array[i].booleanValue(); } return result; } public static boolean[] toPrimitive(Boolean[] array, boolean valueForNull) { if (array == null) { return null; } else if (array.length == 0) { return EMPTY_BOOLEAN_ARRAY; } final boolean[] result = new boolean[array.length]; for (int i = 0; i < array.length; i++) { Boolean b = array[i]; result[i] = (b == null ? valueForNull : b.booleanValue()); } return result; } }