StyledString(String, Font) throws a null pointer exception when both
the String and the Font input parameters are non-null references.

In this tests case, the Font input parameter is constructed using the
Font(AttributeSet) constructor with an empty attribute set. The toString()
method for the resulting font shows: java.awt.Font[family=null,name=null,style=plain,size=0]

The stack trace for the exception shows:
        at java.awt.font.TextAttributeSet.add(TextAttributeSet.java:605)
        at java.awt.font.TextAttributeSet.<init>(TextAttributeSet.java:472)
        at java.awt.font.StyledString.<init>(StyledString.java:136)
        at StyledStringTests.ConstructorFont(StyledStringTests.java:88)
        at java.lang.reflect.Method.invoke(Native Method)
        at javasoft.sqe.jck.lib.MultiTest.run(MultiTest.java:158)
        at StyledStringTests.main(StyledStringTests.java:19)

See the test program below.
   public Status ConstructorFont() {
      StyledString aStyledString;
      String aStringNull = null;
      Font aFontNull = null;
      AttributeSet anAttributeSet = new TextAttributeSet();
      Font aFont = new Font(anAttributeSet);
      // null string and attributes
      try {
         aStyledString = new StyledString(aStringNull, aFontNull);
         return Status.failed("failed to throw NullPointerException for constructor with null string and font references");
      } catch (NullPointerException e) {
         // OKAY
      }
      try {
         aStyledString = new StyledString(aStringNull, aFont);
         return Status.failed("failed to throw NullPointerException for constructor with null string reference and non-null attribute set");
      } catch (NullPointerException e) {
         // OKAY
      }
      try {
         aStyledString = new StyledString("aString", aFontNull);
         return Status.failed("failed to throw NullPointerException for constructor with non-null string reference and null attribute set");
      } catch (NullPointerException e) {
         // OKAY
      }
      try {
         aStyledString = new StyledString("", aFont); //??? Bug, throws exception if string is empty
      } catch (Exception e) {
         System.out.println("failed. " + e + aFont);
         e.printStackTrace();
      }