src/java.base/share/classes/java/util/IllegalFormatConversionException.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
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 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package java.util;

/**
 * Unchecked exception thrown when the argument corresponding to the format
 * specifier is of an incompatible type.
 *
 * <p> Unless otherwise specified, passing a {@code null} argument to any
 * method or constructor in this class will cause a {@link
 * NullPointerException} to be thrown.
 *
 * @since 1.5
 */
public non-sealed class IllegalFormatConversionException extends IllegalFormatException {

    @java.io.Serial
    private static final long serialVersionUID = 17000126L;

    /** @serial */
    private char c;
    /** @serial */
    private Class<?> arg;

    /**
     * Constructs an instance of this class with the mismatched conversion and
     * the corresponding argument class.
     *
     * @param  c
     *         Inapplicable conversion
     *
     * @param  arg
     *         Class of the mismatched argument
     */
    public IllegalFormatConversionException(char c, Class<?> arg) {
        if (arg == null)
            throw new NullPointerException();
        this.c = c;
        this.arg = arg;
    }

    /**
     * Returns the inapplicable conversion.
     *
     * @return  The inapplicable conversion
     */
    public char getConversion() {
        return c;
    }

    /**
     * Returns the class of the mismatched argument.
     *
     * @return   The class of the mismatched argument
     */
    public Class<?> getArgumentClass() {
        return arg;
    }

    // javadoc inherited from Throwable.java
    public String getMessage() {
        return String.format("%c != %s", c, arg.getName());
    }
}