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Java Java Objects (Retired) Delivering the MVP Validation

What's wrong with the line with a comment?

Help.

TeacherAssistant.java
public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    String mFieldName = fieldName;
    if (mFieldName.charAt(0) != 'm') {  //Whats's wrong with this line?
      throw new IllegalArgumentException("Wrong first letter");
    }
    if (Character.toUpperCase(mFieldName.charAt(1)) != mFieldName.charAt(1)) {
      throw new IllegalArgumentException("Wrong second letter");
    }
    // These things should be verified:
    // 1.  Member fields must start with an 'm'
    // 2.  The second letter in the field name must be uppercased to ensure camel-casing
    // NOTE:  To check if something is not equal use the != symbol. eg: 3 != 4
    return fieldName;
  }

}

2 Answers

Romel Liwag
Romel Liwag
4,183 Points

Try this code and happy Coding :)

```public class TeacherAssistant {

public static String validatedFieldName(String fieldName) { // These things should be verified: // 1. Member fields must start with an 'm' // 2. The second letter in the field name must be uppercased to ensure camel-casing // NOTE: To check if something is not equal use the != symbol. eg: 3 != 4 Boolean memberField = fieldName.charAt(0) =='m'; if(!memberField || !Character.isLetter(fieldName.charAt(1)) || fieldName.charAt(1) != Character.toUpperCase(fieldName.charAt(1)) ){ throw new IllegalArgumentException ("Start with 'm' and use camel-casing"); }
return fieldName; } }

The commented line is perfectly fine. It's your second condition that needs fixing. Try this,

if (!Character.isUpperCase(mFieldName.charAt(1))){
      throw new IllegalArgumentException("Wrong second letter");
    }