checker/tests/formatter/VarargsFormatter.java

import java.util.ArrayList;
import java.util.Formatter;

public class VarargsFormatter {
  public static void main(String... p) {
    Formatter f = new Formatter();

    // vararg as parameter
    // :: warning: non-varargs call of varargs method with inexact argument type for last parameter;
    f.format("Nothing", null); // equivalent to (Object[])null
    f.format("Nothing", (Object[]) null);
    f.format("%s", (Object[]) null);
    f.format("%s %d %x", (Object[]) null);
    // :: warning: non-varargs call of varargs method with inexact argument type for last
    // parameter;
    f.format("%s %d %x", null); // equivalent to (Object[])null
    // :: warning: (format.indirect.arguments)
    f.format("%d", new Object[1]);
    // :: warning: (format.indirect.arguments)
    f.format("%s", new Object[2]);
    // :: warning: (format.indirect.arguments)
    f.format("%s %s", new Object[0]);
    // :: warning: (format.indirect.arguments)
    f.format("Empty", new Object[0]);
    // :: warning: (format.indirect.arguments)
    f.format("Empty", new Object[5]);
    f.format("%s", new ArrayList<Object>());
    f.format("%d %s", 132, new Object[2]);
    f.format("%s %d", new Object[2], 123);
    // :: error: (format.missing.arguments)
    f.format("%d %s %s", 132, new Object[2]);
    // :: error: (argument)
    f.format("%d %d", new Object[2], 123);
    // "error: (format.specifier.null)" could be a warning rather than an error, but that would
    // require reasoning about the values in an array construction expression.
    // :: error: (format.specifier.null) :: warning: (format.indirect.arguments)
    f.format("%d %<f", new Object[1]);

    // too many arguments
    // :: warning: (format.excess.arguments)
    f.format("", 213);
    // :: warning: (format.excess.arguments)
    f.format("%d", 232, 132);
    // :: warning: (format.excess.arguments)
    f.format("%s", "a", "b");
    // :: warning: (format.excess.arguments)
    f.format("%d %s", 123, "a", 123);

    // too few arguments
    // :: error: (format.missing.arguments)
    f.format("%s");
    // :: error: (format.missing.arguments)
    f.format("%d %s", 545);
    // :: error: (format.missing.arguments)
    f.format("%s %c %c", 'c', 'c');

    f.close();
  }
}