How to mock static methods during unit testing?

Well, static mock is not implemented in Mockito, so we have to use PowerMock to achieve this:

Let's say we have the following class:

package com;

import java.net.InetAddress;
import java.net.UnknownHostException;

public final class SystemUtils {

   public static final String UNKNOWN_HOST = "Unknown";

   public static String getHostName() {
      String hostname = UNKNOWN_HOST;
      try {
         InetAddress addr = InetAddress.getLocalHost();
         // Get hostname
         hostname = addr.getHostName();
      } catch (UnknownHostException e ) {
         System.out.println("catch UnknownHostException...");
      }
      return hostname;
   }
}

and we need to test that UnknownHostException is thrown.
So our goal is to mock InetAddress.getLocalHost() and ask it to return an exception so SystemUtils.getHostName() will return 'Unknown'.

First import all needful libs:

<properties>

    <junit.version>4.11</junit.version>

    <mockito.version>1.10.19</mockito.version>

    <powermock.version>1.6.2</powermock.version>

</properties>

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>${junit.version}</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-all</artifactId>
    <version>${mockito.version}</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-api-mockito</artifactId>
    <version>${powermock.version}</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-module-junit4</artifactId>
    <version>${powermock.version}</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-module-junit4-rule</artifactId>
    <version>${powermock.version}</version>
    <scope>test</scope>
</dependency>

And test would look the following way:

import com.SystemUtils;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.internal.stubbing.answers.ThrowsExceptionClass;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.net.InetAddress;
import java.net.UnknownHostException;
import static org.junit.Assert.assertEquals;


@RunWith(PowerMockRunner.class)
@PrepareForTest(SystemUtils.class)
public class SystemUtilsTest {

    @Test
    public void testGetHostName() throws UnknownHostException {
        PowerMockito.mockStatic(InetAddress.class);
        PowerMockito.when(InetAddress.getLocalHost())
                .then(new ThrowsExceptionClass(UnknownHostException.class));
        String actualValue = SystemUtils.getHostName();
        assertEquals("On exception expected unknown value", SystemUtils.UNKNOWN_HOST, actualValue);
    }
}