I want to call a java method once in the background of a feature file, assign the value of the method to a variable and share it across scenarios

Question

java class

public class Utilities {


    public static String generateRandomString(int length) {
        String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        StringBuilder sb = new StringBuilder(length);
        for (int i = 0; i < length; i++) {
            int index = (int) (Math.random() * chars.length());
            sb.append(chars.charAt(index));
        }
        return sb.toString();
    }
}

Feature file

Background:
    * def RandomStringGenerator = Java.type('Utilities')
    * def randomString = callonce RandomStringGenerator.generateRandomString(10)
    * print 'a'+randomString

  Scenario: Use Random String
    * print 'b'+randomString

  Scenario: Use Random String in scenario2
    * print 'c'+randomString

The randomString is printing null instead of the string generated. i am using karate 0.9.5 version if that helps

Answer 1

Call the static Java method via JavaScript. You have missed to add package name of the java class Utilities. Replace the feature file like below.

Feature: call java static method

  Background: 
    * def generateData =
      """
      function(arg) {
      var JavaDemo = Java.type('com.tests.Utilities');
      
      return JavaDemo.generateRandomString(arg);  
      }
      """
    * def result = callonce generateData 10
    * print 'a'+result

  Scenario: Use same string value scenario1
    * print 'b'+result

  Scenario: Use same string value scenario2 
    * print 'c'+result

Official Karate Doc: https://github.com/karatelabs/karate#calling-java