ManualExample.java

// Example from the manual

import static org.checkerframework.checker.formatter.qual.ConversionCategory.FLOAT;
import static org.checkerframework.checker.formatter.qual.ConversionCategory.INT;

import org.checkerframework.checker.formatter.qual.Format;

public class ManualExample {

    void m(boolean flag) {

        @Format({FLOAT, INT}) String f;

        f = "%f %d"; // OK
        f = "%s %d"; // OK, %s is weaker than %f
        //:: warning: (format.missing.arguments)
        f = "%f"; // warning: last argument is ignored
        //:: warning: (format.missing.arguments)
        f = flag ? "%f %d" : "%f";

        if (flag) {
            f = "%f %d";
        } else {
            //:: warning: (format.missing.arguments)
            f = "%f";
        }
        @Format({FLOAT, INT}) String f2 = f;

        //:: error: (assignment.type.incompatible)
        f = "%f %d %s"; // error: too many arguments
        //:: error: (assignment.type.incompatible)
        f = "%d %d"; // error: %d is not weaker than %f

        String.format(f, 0.8, 42);
    }
}