This is a first batch of simple modernization of the codebase

I threw airsonic at IntelliJ's IDEA analysis,
and asked it to flag what could be modernized
for Java > 5.

- foreach instead of for…
- I added some null-deref checks
- Integer.ValueOf, since Integer(…) is deprecated
- Contextual try
- Objects.equals instead of handcrafted comparisons
- StringBuilder instead of StringBuffer
- Removal of outdated/wrong javadoc comments

airsonic-main/src/main/java/org/airsonic/player/ajax/TagService.java

@@ -73,7 +73,7 @@ public class TagService {
         Integer trackNumber = null;
         if (track != null) {
             try {
-                trackNumber = new Integer(track);
+                trackNumber = Integer.valueOf(track);
             } catch (NumberFormatException x) {
                 LOG.warn("Illegal track number: " + track, x);
             }
@@ -82,7 +82,7 @@ public class TagService {
         Integer yearNumber = null;
         if (year != null) {
             try {
-                yearNumber = new Integer(year);
+                yearNumber = Integer.valueOf(year);
             } catch (NumberFormatException x) {
                 LOG.warn("Illegal year: " + year, x);
             }

airsonic-main/src/main/java/org/airsonic/player/controller/DownloadController.java

@@ -368,9 +368,8 @@ public class DownloadController implements LastModified {
      */
     private long computeCrc(File file) throws IOException {
         CRC32 crc = new CRC32();
-        InputStream in = new FileInputStream(file);
 
-        try {
+        try (InputStream in = new FileInputStream(file)) {
 
             byte[] buf = new byte[8192];
             int n = in.read(buf);
@@ -379,8 +378,6 @@ public class DownloadController implements LastModified {
                 n = in.read(buf);
             }
 
-        } finally {
-            in.close();
         }
 
         return crc.getValue();

airsonic-main/src/main/java/org/airsonic/player/controller/PlayerSettingsController.java

@@ -106,8 +106,9 @@ public class PlayerSettingsController  {
         command.setAdmin(user.isAdminRole());
 
         command.setJavaJukeboxMixers(Arrays.stream(AudioSystemUtils.listAllMixers()).map(info -> info.getName()).toArray(String[]::new));
-        command.setJavaJukeboxMixer(player.getJavaJukeboxMixer());
-
+        if (player != null) {
+            command.setJavaJukeboxMixer(player.getJavaJukeboxMixer());
+        }
         model.addAttribute("command",command);
     }
 

airsonic-main/src/main/java/org/airsonic/player/controller/UploadController.java

@@ -166,9 +166,7 @@ public class UploadController {
     private void unzip(File file, List<File> unzippedFiles) throws Exception {
         LOG.info("Unzipping " + file);
 
-        ZipFile zipFile = new ZipFile(file);
-
-        try {
+        try (ZipFile zipFile = new ZipFile(file)) {
 
             Enumeration<?> entries = zipFile.entries();
 
@@ -210,8 +208,6 @@ public class UploadController {
             zipFile.close();
             file.delete();
 
-        } finally {
-            zipFile.close();
         }
     }
 

airsonic-main/src/main/java/org/airsonic/player/domain/MusicIndex.java

@@ -24,6 +24,7 @@ import java.text.CollationKey;
 import java.text.Collator;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * A music index is a mapping from an index string to a list of prefixes.  A complete index consists of a list of
@@ -99,7 +100,7 @@ public class MusicIndex implements Serializable {
 
         final MusicIndex musicIndex = (MusicIndex) o;
 
-        if (index != null ? !index.equals(musicIndex.index) : musicIndex.index != null) {
+        if (!Objects.equals(index, musicIndex.index)) {
             return false;
         }
 

airsonic-main/src/main/java/org/airsonic/player/domain/PlayQueue.java

@@ -215,9 +215,7 @@ public class PlayQueue {
         }
         files.remove(index);
 
-        if (index != -1) {
-            this.index = Math.max(0, Math.min(this.index, size() - 1));
-        }
+        this.index = Math.max(0, Math.min(this.index, size() - 1));
     }
 
     /**

airsonic-main/src/main/java/org/airsonic/player/domain/Transcoding.java

@@ -21,6 +21,8 @@ package org.airsonic.player.domain;
 
 import org.airsonic.player.util.StringUtil;
 
+import java.util.Objects;
+
 /**
  * Contains the configuration for a transcoding, i.e., a specification of how a given media format
  * should be converted to another.
@@ -213,7 +215,7 @@ public class Transcoding {
         }
 
         Transcoding that = (Transcoding) o;
-        return !(id != null ? !id.equals(that.id) : that.id != null);
+        return Objects.equals(id, that.id);
     }
 
     public int hashCode() {

airsonic-main/src/main/java/org/airsonic/player/domain/User.java

@@ -206,7 +206,7 @@ public class User {
 
     @Override
     public String toString() {
-        StringBuffer result = new StringBuffer(username);
+        StringBuilder result = new StringBuilder(username);
 
         if (isAdminRole) {
             result.append(" [admin]");

airsonic-main/src/main/java/org/airsonic/player/io/TranscodeInputStream.java

@@ -56,7 +56,7 @@ public class TranscodeInputStream extends InputStream {
     public TranscodeInputStream(ProcessBuilder processBuilder, final InputStream in, File tmpFile) throws IOException {
         this.tmpFile = tmpFile;
 
-        StringBuffer buf = new StringBuffer("Starting transcoder: ");
+        StringBuilder buf = new StringBuilder("Starting transcoder: ");
         for (String s : processBuilder.command()) {
             buf.append('[').append(s).append("] ");
         }

airsonic-main/src/main/java/org/airsonic/player/monitor/MetricsManager.java

@@ -49,7 +49,7 @@ public class MetricsManager {
                 }
             }
         }
-        return metricsActivatedByConfiguration.booleanValue();
+        return metricsActivatedByConfiguration;
     }
 
     /**

airsonic-main/src/main/java/org/airsonic/player/service/MediaFileService.java

@@ -347,10 +347,6 @@ public class MediaFileService {
     /**
      * Returns random songs matching search criteria.
      *
-     * @param criteria Random search criteria.
-     * @param count    Max number of songs to return.
-     * @return Random songs
-     * @see SearchService.getRandomSongs
      */
     public List<MediaFile> getRandomSongs(RandomSearchCriteria criteria, String username) {
         return mediaFileDao.getRandomSongs(criteria, username);

airsonic-main/src/main/java/org/airsonic/player/service/MusicIndexService.java

@@ -265,13 +265,7 @@ public class MusicIndexService {
                 indexB = Integer.MAX_VALUE;
             }
 
-            if (indexA < indexB) {
-                return -1;
-            }
-            if (indexA > indexB) {
-                return 1;
-            }
-            return 0;
+            return Integer.compare(indexA, indexB);
         }
     }
 }

airsonic-main/src/main/java/org/airsonic/player/service/PodcastService.java

@@ -450,7 +450,7 @@ public class PodcastService {
             if (getEpisodeByUrl(url) == null) {
                 Long length = null;
                 try {
-                    length = new Long(enclosure.getAttributeValue("length"));
+                    length = Long.valueOf(enclosure.getAttributeValue("length"));
                 } catch (Exception x) {
                     LOG.warn("Failed to parse enclosure length.", x);
                 }
@@ -470,13 +470,7 @@ public class PodcastService {
                 long timeA = a.getPublishDate() == null ? 0L : a.getPublishDate().getTime();
                 long timeB = b.getPublishDate() == null ? 0L : b.getPublishDate().getTime();
 
-                if (timeA < timeB) {
-                    return 1;
-                }
-                if (timeA > timeB) {
-                    return -1;
-                }
-                return 0;
+                return Long.compare(timeB, timeA);
             }
         });
 

airsonic-main/src/main/java/org/airsonic/player/service/SecurityService.java

@@ -96,8 +96,8 @@ public class SecurityService implements UserDetailsService {
         List<GrantedAuthority> authorities = new ArrayList<>();
         authorities.add(new SimpleGrantedAuthority("IS_AUTHENTICATED_ANONYMOUSLY"));
         authorities.add(new SimpleGrantedAuthority("ROLE_USER"));
-        for (int i = 0; i < roles.length; i++) {
-            authorities.add(new SimpleGrantedAuthority("ROLE_" + roles[i].toUpperCase()));
+        for (String role : roles) {
+            authorities.add(new SimpleGrantedAuthority("ROLE_" + role.toUpperCase()));
         }
         return authorities;
     }

airsonic-main/src/main/java/org/airsonic/player/service/metadata/JaudiotaggerParser.java

@@ -161,7 +161,7 @@ public class JaudiotaggerParser extends MetaDataParser {
         Integer result = null;
 
         try {
-            result = new Integer(trackNumber);
+            result = Integer.valueOf(trackNumber);
         } catch (NumberFormatException x) {
             Matcher matcher = TRACK_NUMBER_PATTERN.matcher(trackNumber);
             if (matcher.matches()) {
@@ -187,7 +187,7 @@ public class JaudiotaggerParser extends MetaDataParser {
         Integer result = null;
 
         try {
-            result = new Integer(year);
+            result = Integer.valueOf(year);
         } catch (NumberFormatException x) {
             Matcher matcher = YEAR_NUMBER_PATTERN.matcher(year);
             if (matcher.matches()) {

airsonic-main/src/main/java/org/airsonic/player/taglib/UrlTag.java

@@ -88,7 +88,7 @@ public class UrlTag extends BodyTagSupport {
     private String formatUrl() throws JspException {
         String baseUrl = UrlSupport.resolveUrl(value, null, pageContext);
 
-        StringBuffer result = new StringBuffer();
+        StringBuilder result = new StringBuilder();
         result.append(baseUrl);
         if (!parameters.isEmpty()) {
             result.append('?');

airsonic-main/src/main/java/org/airsonic/player/util/StringUtil.java

@@ -30,10 +30,7 @@ import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.security.MessageDigest;
 import java.text.*;
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.List;
-import java.util.Locale;
+import java.util.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -327,7 +324,7 @@ public final class StringUtil {
      * @return Whether a and b are equal, or both null.
      */
     public static boolean isEqual(Object a, Object b) {
-        return a == null ? b == null : a.equals(b);
+        return Objects.equals(a, b);
     }
 
     /**