Could not create query for public abstract

When encountering the error message “could not create query for public abstract”, it typically means that there is an issue with the query being executed, specifically with a public abstract method.

A public abstract method is a method declaration without a body, meaning it doesn’t contain any implementation details. It is a placeholder for the actual implementation that needs to be provided by a concrete subclass. However, when trying to execute a query using this public abstract method, the query processor cannot determine how to handle the method without a specific implementation.

To fix this issue, you need to either provide a concrete implementation for the abstract method or remove the abstract declaration if it is not needed. Here are a few examples to illustrate these scenarios:

Example 1: Providing a Concrete Implementation

    
      public abstract class AbstractClass {
          public abstract void doSomething();
      
          public void displayMessage() {
              System.out.println("Hello, world!");
          }
      }
      
      public class ConcreteClass extends AbstractClass {
          public void doSomething() {
              System.out.println("Doing something...");
          }
      }
      
      public class Main {
          public static void main(String[] args) {
              AbstractClass instance = new ConcreteClass();
              instance.doSomething();
              instance.displayMessage();
          }
      }
    
  

In this example, we define an abstract class (AbstractClass) with a public abstract method (doSomething()). The AbstractClass also provides a concrete method (displayMessage()) with an implementation.

To use the abstract class, we create a concrete subclass (ConcreteClass) that extends AbstractClass and provides an implementation for the doSomething() method. In the Main class, we create an instance of ConcreteClass and invoke both the doSomething() and displayMessage() methods.

By providing a concrete implementation, there should be no issues executing the query for the public abstract method.

Example 2: Removing the Abstract Declaration

    
      public abstract class AbstractClass {
          public void doSomething() {
              System.out.println("Doing something...");
          }
      
          public void displayMessage() {
              System.out.println("Hello, world!");
          }
      }
      
      public class Main {
          public static void main(String[] args) {
              AbstractClass instance = new AbstractClass();
              instance.doSomething();
              instance.displayMessage();
          }
      }
    
  

In this example, we modify the AbstractClass by removing the abstract declaration from the doSomething() method. The class now has a concrete implementation for both methods.

However, since the AbstractClass no longer contains any abstract methods, it can be instantiated directly. In the Main class, we create an instance of AbstractClass and invoke both methods without any issues.