Use try-with-resource.

src/main/java/org/apache/commons/mail/ByteArrayDataSource.java

@@ -71,20 +71,10 @@ public class ByteArrayDataSource implements DataSource
     public ByteArrayDataSource(final byte[] data, final String aType) throws IOException
     {
         this.type = aType;
-        ByteArrayInputStream bis = null;
-
-        try
+        try (ByteArrayInputStream bis = new ByteArrayInputStream(data))
         {
-            bis = new ByteArrayInputStream(data);
             this.byteArrayDataSource(bis);
         }
-        finally
-        {
-            if (bis != null)
-            {
-                bis.close();
-            }
-        }
     }
 
     /**

src/main/java/org/apache/commons/mail/util/MimeMessageUtils.java

@@ -53,20 +53,10 @@ private MimeMessageUtils()
     public static MimeMessage createMimeMessage(final Session session, final byte[] source)
         throws MessagingException, IOException
     {
-        ByteArrayInputStream is = null;
-
-        try
+        try (ByteArrayInputStream is = new ByteArrayInputStream(source))
         {
-            is = new ByteArrayInputStream(source);
             return new MimeMessage(session, is);
         }
-        finally
-        {
-            if (is != null)
-            {
-                is.close();
-            }
-        }
     }
 
     /**
@@ -81,20 +71,10 @@ public static MimeMessage createMimeMessage(final Session session, final byte[]
     public static MimeMessage createMimeMessage(final Session session, final File source)
         throws MessagingException, IOException
     {
-        FileInputStream is = null;
-
-        try
+        try (FileInputStream is = new FileInputStream(source))
         {
-            is = new FileInputStream(source);
             return createMimeMessage(session, is);
         }
-        finally
-        {
-            if (is != null)
-            {
-                is.close();
-            }
-        }
     }
 
     /**

src/test/java/org/apache/commons/mail/resolver/AbstractDataSourceResolverTest.java

@@ -31,11 +31,8 @@ protected byte[] toByteArray(final DataSource dataSource) throws IOException
     {
         if(dataSource != null)
         {
-            final InputStream is = dataSource.getInputStream();
-            try {
+            try (InputStream is = dataSource.getInputStream()) {
                 return IOUtils.toByteArray(is);
-            } finally {
-                is.close();
             }
         }
         return null;