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npathainpathai
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Work on iluwatar#385, added documentation and class diagram. Made refactoring changes to pass checkstyle and PMD checks
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Lines changed: 106 additions & 18 deletions

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‎mute-idiom/etc/mute-idiom.png‎

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‎mute-idiom/etc/mute-idiom.ucls‎

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<?xml version="1.0" encoding="UTF-8"?>
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<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true"
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realizations="true" associations="true" dependencies="true" nesting-relationships="true">
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<class id="1" language="java" name="com.iluwatar.mute.App" project="mute-idiom"
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file="/mute-idiom/src/main/java/com/iluwatar/mute/App.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="519" y="122"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="false" static="true"/>
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<operations public="true" package="true" protected="true" private="false" static="true"/>
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</display>
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</class>
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<class id="2" language="java" name="com.iluwatar.mute.Mute" project="mute-idiom"
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file="/mute-idiom/src/main/java/com/iluwatar/mute/Mute.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="115" width="203" x="291" y="267"/>
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<display autosize="false" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="false" static="true"/>
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</display>
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</class>
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<interface id="3" language="java" name="com.iluwatar.mute.CheckedRunnable" project="mute-idiom"
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file="/mute-idiom/src/main/java/com/iluwatar/mute/CheckedRunnable.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="723" y="322"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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</display>
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</interface>
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<dependency id="4">
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<end type="SOURCE" refId="1"/>
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<end type="TARGET" refId="2"/>
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</dependency>
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<dependency id="5">
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<end type="SOURCE" refId="2"/>
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<end type="TARGET" refId="3"/>
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</dependency>
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<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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</classifier-display>
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<association-display labels="true" multiplicity="true"/>
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</class-diagram>

‎mute-idiom/src/main/java/com/iluwatar/mute/App.java‎

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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.mute;
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import static org.mockito.Mockito.doThrow;
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import java.io.ByteArrayOutputStream;
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import java.sql.Connection;
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import java.sql.SQLException;
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import java.sql.Statement;
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/**
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* Mute pattern is utilized when we need to suppress an exception due to an API flaw or in
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* situation when all we can do to handle the exception is to log it.
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* This pattern should not be used everywhere. It is very important to logically handle the
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* exceptions in a system, but some situations like the ones described above require this pattern,
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* so that we don't need to repeat
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* <pre>
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* <code>
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* try {
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* // code that may throwing exception we need to ignore or may never be thrown
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* } catch (Exception ex) {
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* // ignore by logging or throw error if unexpected exception occurs
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* }
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* </code>
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* </pre> every time we need to ignore an exception.
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*
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*/
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public class App {
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public static void main(String[] args) {
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/**
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* Program entry point.
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*
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* @param args command line args.
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* @throws Exception if any exception occurs
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*/
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public static void main(String[] args) throws Exception {
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useOfLoggedMute();
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useOfMute();
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}
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/*
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* Typically used when the API declares some exception but cannot do so. Usually a signature mistake.
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* In this example out is not supposed to throw exception as it is a ByteArrayOutputStream. So we
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* utilize mute, which will throw AssertionError if unexpected exception occurs.
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* Typically used when the API declares some exception but cannot do so. Usually a
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* signature mistake.In this example out is not supposed to throw exception as it is a
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* ByteArrayOutputStream. So we utilize mute, which will throw AssertionError if unexpected
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* exception occurs.
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*/
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private static void useOfMute() {
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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Mute.mute(() -> out.write("Hello".getBytes()));
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}
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private static void useOfLoggedMute() {
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private static void useOfLoggedMute() throws SQLException {
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Connection connection = null;
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try {
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connection = openConnection();
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readStuff(connection);
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} catch (SQLException ex) {
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ex.printStackTrace();
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} finally {
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closeConnection(connection);
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}
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* All we can do while failed close of connection is to log it.
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*/
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private static void closeConnection(Connection connection) {
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if (connection != null) {
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Mute.loggedMute(() -> connection.close());
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}
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Mute.loggedMute(() -> connection.close());
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}
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private static void readStuff(Connection connection) throws SQLException {
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if (connection != null) {
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connection.createStatement();
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try (Statement statement = connection.createStatement()) {
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System.out.println("Read data from statement");
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}
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}
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‎mute-idiom/src/main/java/com/iluwatar/mute/CheckedRunnable.java‎

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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.mute;
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/**
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* Same as {@link Runnable#run()} with a possibility of exception in execution.
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* @throws Exception if any exception occurs.
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*/
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public void run() throws Exception;
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void run() throws Exception;
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}

‎mute-idiom/src/main/java/com/iluwatar/mute/Mute.java‎

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* A utility class that allows you to utilize mute idiom.
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*/
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public final class Mute {
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// The constructor is never meant to be called.
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private Mute() {}
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/**
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* Executes the <code>runnable</code> and throws the exception occurred within a {@link AssertionError}.

‎mute-idiom/src/test/java/com/iluwatar/mute/AppTest.java‎

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public class AppTest {
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@Test
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public void test() {
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public void test() throws Exception {
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App.main(null);
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}
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}

‎mute-idiom/src/test/java/com/iluwatar/mute/MuteTest.java‎

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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.mute;
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import static org.junit.Assert.assertTrue;
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@Rule public ExpectedException exception = ExpectedException.none();
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@Test
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public void muteShouldRunTheCheckedRunnableAndNotThrowAnyExceptionIfCheckedRunnableDoesNotThrowAnyException() {
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Mute.mute(() -> methodNotThrowingAnyException());
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}
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@Test
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public void muteShouldRethrowUnexpectedExceptionAsAssertionError() throws Exception {
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exception.expect(AssertionError.class);
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Mute.mute(() -> methodThrowingException());
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}
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private void methodThrowingException() throws Exception {
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throw new Exception(MESSAGE);
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@Test
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public void loggedMuteShouldRunTheCheckedRunnableAndNotThrowAnyExceptionIfCheckedRunnableDoesNotThrowAnyException() {
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Mute.loggedMute(() -> methodNotThrowingAnyException());
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}
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@Test
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assertTrue(new String(stream.toByteArray()).contains(MESSAGE));
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}
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private void methodNotThrowingAnyException() {
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System.out.println("Executed successfully");
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}
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private void methodThrowingException() throws Exception {
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throw new Exception(MESSAGE);
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}
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}

‎pom.xml‎

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<module>feature-toggle</module>
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<module>value-object</module>
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<module>monad</module>
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<module>mute-idiom</module>
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</modules>
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<dependencyManagement>

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