java - What can an Object[] array hold? -
i new java programming language , had question arrays. string[]
arrays hold strings. array[]
arrays hold other arrays. object[]
array? clearly, these hold object
s. but, since object
superclass in java, mean object[]
array can hold every type of object
in java? in other words, can array hold objects child classes of object array created hold? can number[]
array hold integer?
yes can learn lot trying small program:
public class example { public static void main(string[] args) { string string = "string"; integer integer = new integer(1); int integerprimitive = 2; float floatboxed = new float(1.23); float floatprimitive = 1.23f; // can hold different types inheriting object object[] objects = new object[] { string, integer, integerprimitive, floatboxed, floatprimitive }; // can hold inherits number; cannot hold string number[] numbers = new number[] { integer, integerprimitive, floatboxed, floatprimitive }; (int = 0; < objects.length; i++) { system.out.println("objects[" + + "] = " + objects[i]); } (int = 0; < numbers.length; i++) { system.out.println("numbers[" + + "] = " + numbers[i]); } } }
output:
objects[0] = string objects[1] = 1 objects[2] = 2 objects[3] = 1.23 objects[4] = 1.23 numbers[0] = 1 numbers[1] = 2 numbers[2] = 1.23 numbers[3] = 1.23
the key knowing array container can hold first observing if object types same or if object sub-class of array container type.
in question if number
can hold integer
, should see inheritance of integer
in javadocs inherits number
. can see number
inherits object
.
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