"Cannot create generic array of .." - how to create an Array of Map<String, Object> in java?

"Cannot create generic array of .." - how to create an Array of Map<String, Object> in java?

In Java, you cannot create an array of a generic type directly because of type erasure. However, you can work around this limitation by creating an array of a wildcard type (?) and then casting it. Here's how you can create an array of Map<String, Object>:

@SuppressWarnings("unchecked") public class ArrayOfMapExample { public static void main(String[] args) { // Create an array of raw Map type Map<String, Object>[] arrayOfMaps = new Map[10]; // You can now create instances of Map<String, Object> Map<String, Object> map1 = new HashMap<>(); map1.put("key1", "value1"); map1.put("key2", 42); Map<String, Object> map2 = new HashMap<>(); map2.put("name", "John"); map2.put("age", 30); // Assign the maps to the array arrayOfMaps[0] = map1; arrayOfMaps[1] = map2; // Access the maps from the array System.out.println(arrayOfMaps[0]); System.out.println(arrayOfMaps[1]); } }

In this example:

  1. We create an array arrayOfMaps of type Map[] (a raw type).

  2. We then create instances of Map<String, Object> and assign them to elements of the array.

  3. We use @SuppressWarnings("unchecked") to suppress the unchecked warning, as you are effectively bypassing type checking when working with raw types.

While this approach allows you to create an array of Map<String, Object>, keep in mind that using raw types can lead to type-related issues and is generally discouraged. It's often better to use collections like ArrayList or List<Map<String, Object>> instead of arrays when dealing with generic types in Java.

More Tags

polish bash android-paging-library array-broadcasting idp xml-parsing percentile spring-boot-maven-plugin chart.js unauthorizedaccessexcepti

More Java Questions

More Investment Calculators

More Gardening and crops Calculators

More Weather Calculators

More Housing Building Calculators