I need to mock a static method, so that it throws an exception the first time it is called, and returns some value, the second time it is called. I know how to mock it so that it throws an exception and mock it so that it returns a value, but am not sure how to make it behave differently on two subsequent calls.

Also, how would I test two subsequent calls to a mocked static method in a single test? Would I be able to do it in one MockedStatic block or do I need two separate Mocked static blocks for each call? This question will make more sense in the example below:

/** Util class containing static. method to be mocked */
public final class VariableUtil {   
            
  //. static method to be mocked.
  public static JsonValue createJsonVariable(Object variableValue) throws Exception{…..}
}
    
/** JsonValue class */
public interface JsonValue extends PrimitiveValue<String> {
}

/** Class that uses the VariableUtil class */
public class SomeClass {

    //. Method that makes two calls to the static method.
    public void someMethod() {
    
        try {
            //. Make the FIRST call to the static method.
            //. This time it SHOULD throw an exception

            VariableUtil.createVariable(
                Collections.singletonList(someObject));

        } catch(Exception ex) {
            //. The first call’s exception should bring execution into 
            //. this catch block, where we,  
            //. make the SECOND call to the static method.  This time 
            //. it SHOULD NOT throw an exception and instead return a mocked value.

            JsonValue someJsonValue = VariableUtil.createVariable(
                Collections.singletonList(someObject));
        }
    }
}

/**.JUnit.*/:
@Test
public void testCreateVariable() {

    //. The below DOES NOT WORK.  How would I mock it so that, 
    //. on the first invocation, it throws an Exception 
    //. and, on the second, it returns a value?
 
    try (final MockedStatic<VariableUtil> variableUtilMock = 

        //. Mock throwing an exception.
        mockStatic(VariableUtil.class)) {
          variableUtilMock.when(() -> VariableUtil.createJsonVariable(processingFailureErrorMessage))
                .thenThrow(new Exception());
        
        //. Mock returning a value.
        variableUtilMock.when(() -> VariableUtil.createJsonVariable(processingFailureErrorMessage))
                .thenReturn("someJsonValue");
            
            SomeClass someObject = new SomeClass();
            someObject.someMethod();
        }
}