Example

public class ClassA {
private final String stringObject = "A new String";
private String nonConstantString = "Changing String";

public void method() {
String localString = "append";
nonConstantString += localString;
}
}

Solution
A non-constant String object should be declared as a StringBuffer instead. Any changes to the String should be done with the append() class of StringBuffer.

public class ClassA {
private final String stringObject = "A new String";
private StringBuffer nonConstantString = new StringBuffer("Changing String");

public void method() {
String localString = "append";
nonConstantString.append(localString);
}
}