Fixes some warnings

src/main/java/net/knarcraft/ffmpegconverter/utility/FFMpegHelper.java

@@ -110,7 +110,7 @@ public final class FFMpegHelper {
         StringBuilder output = new StringBuilder();
         while (process.isAlive()) {
             String read = readProcess(processReader, spacer);
-            if (!read.equals("")) {
+            if (!read.isEmpty()) {
                 if (write) {
                     OutputUtil.println(read);
                 } else {
@@ -339,7 +339,7 @@ public final class FFMpegHelper {
     private static String readProcess(BufferedReader reader, String spacer) throws IOException {
         String line;
         StringBuilder text = new StringBuilder();
-        while (reader.ready() && (line = reader.readLine()) != null && !line.equals("") && !line.equals("\n")) {
+        while (reader.ready() && (line = reader.readLine()) != null && !line.isEmpty() && !line.equals("\n")) {
             text.append(line).append(spacer);
         }
         return text.toString().trim();

src/main/java/net/knarcraft/ffmpegconverter/utility/OutputUtil.java

@@ -32,7 +32,7 @@ public final class OutputUtil {
      * @throws IOException <p>If a write is not possible.</p>
      */
     public static void println(String input) throws IOException {
-        if (!input.equals("")) {
+        if (!input.isEmpty()) {
             writer.write(input);
         }
         println();

src/main/java/net/knarcraft/ffmpegconverter/utility/Parser.java

@@ -193,7 +193,7 @@ public final class Parser {
      * @return <p>True if the string builder is non empty.</p>
      */
     private static boolean isNotEmpty(StringBuilder builder) {
-        return !builder.toString().trim().equals("");
+        return !builder.toString().trim().isEmpty();
     }
 
 }