How to get user input in Java

In Java, we can use java.util.Scanner to get user input from console.

Date: 2019-08-11 View: 1689

Start a Java class and hits this java.lang.UnsupportedClassVersionError, what is class file version 52 56?

Date: 2019-08-11 View: 1647

How to check which JDK version compiled the class?

In Java, we can use javap -verbose className to print out the class information.

Date: 2019-08-11 View: 1405

In the old days, we can use list.toArray(new String[0]) to convert a ArrayList<String> into a String[]

Date: 2019-08-11 View: 1547

Gson provide simple toJson() and fromJson() methods to convert Java objects to / from JSON.

Date: 2019-08-11 View: 1708

Few Jackson examples to convert a JSON array string to a List

Date: 2019-08-11 View: 1894

In Jackson, we can use @JsonInclude(JsonInclude.Include.NON_NULL) to ignore the null fields.

Date: 2019-08-11 View: 1740

Jackson provide writeValue() and readValue() methods to convert Java objects to / from JSON.

Date: 2019-08-11 View: 1553

In Jackson, we can use @JsonView to limit or control fields display for different users.

Date: 2019-08-11 View: 1777

In Java, we can use (str != null && !str.isEmpty()) to make sure the String is not empty or null.

Date: 2019-08-11 View: 1413

Few Java examples to show you how to check if a String is numeric.

Date: 2019-08-11 View: 1456

In this tutorial, we will show you how to parse JSON with JSON.simple

Date: 2019-08-11 View: 1802

In Java, we can use new ArrayList<>(Arrays.asList(array)) to convert an Array into an ArrayList

Date: 2019-08-11 View: 1421

In Java, we can use Double.parseDouble() to convert a String to double

Date: 2019-08-11 View: 1784

Few Java examples to show you how to generate a random alphanumeric String, with a fixed length.

Date: 2019-08-11 View: 1651