Make String.format(“%s”, arg) display null-valued arguments differently from “null”

Question

Consider the custom toString() implementation of a bean:

@Override
public String toString() {
    String.format(\"this is %s\", this.someField);
}
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Answer 1

From java 7, you can use Objects.toString(Object o, String nullDefault).

Applied to your example: String.format("this is %s", Objects.toString(this.someField, "?"));