Resource Leaks in processing/app/Util.java (#1436)

* Add java tests to build path

to put the test in the appropriate directory, id have to java files to
grade build configs, because it currently only checks for kotlin tests.

* Unit test for rsrc leakage in unzip

create a temp zip file > create a destination that is a file not a
directory (guaranteed exception) -> unzip throws ioexception because it
expects a directory not a file -> catch it -> check if the zip file is
still open -> if true == leak.

* Add try() to manage opened files/rsrcs

* Applying try() to more rsrcs

Ive also removed the test since its OS specific, and new code is
supposed to be in kotlin.

Author: SalmaneKhalili

app/src/processing/app/Util.java

@@ -60,16 +60,17 @@ static public int countLines(String what) {
    */
   static public byte[] loadBytesRaw(File file) throws IOException {
     int size = (int) file.length();
-    FileInputStream input = new FileInputStream(file);
-    byte[] buffer = new byte[size];
-    int offset = 0;
-    int bytesRead;
-    while ((bytesRead = input.read(buffer, offset, size-offset)) != -1) {
-      offset += bytesRead;
-      if (bytesRead == 0) break;
-    }
-    input.close();  // weren't properly being closed
-    return buffer;
+      byte[] buffer;
+      try (FileInputStream input = new FileInputStream(file)) {
+          buffer = new byte[size];
+          int offset = 0;
+          int bytesRead;
+          while ((bytesRead = input.read(buffer, offset, size - offset)) != -1) {
+              offset += bytesRead;
+              if (bytesRead == 0) break;
+          }
+      }
+      return buffer;
   }
 
 
@@ -143,7 +144,7 @@ static public StringDict readSettings(String filename, String[] lines, boolean a
         line = line.substring(0, line.indexOf('#')).trim();
       }
 
-      if (line.length() != 0 && line.charAt(0) != '#') {
+      if (!line.isEmpty() && line.charAt(0) != '#') {
         int equals = line.indexOf('=');
         if (equals == -1) {
           if (filename != null) {
@@ -161,26 +162,20 @@ static public StringDict readSettings(String filename, String[] lines, boolean a
   }
 
 
-  static public void copyFile(File sourceFile,
-                              File targetFile) throws IOException {
-    BufferedInputStream from =
-      new BufferedInputStream(new FileInputStream(sourceFile));
-    BufferedOutputStream to =
-      new BufferedOutputStream(new FileOutputStream(targetFile));
+  static public void copyFile(File sourceFile, File targetFile) throws IOException {
+    try (
+    BufferedInputStream from = new BufferedInputStream(new FileInputStream(sourceFile));
+    BufferedOutputStream to = new BufferedOutputStream(new FileOutputStream(targetFile))) {
     byte[] buffer = new byte[16 * 1024];
     int bytesRead;
     while ((bytesRead = from.read(buffer)) != -1) {
       to.write(buffer, 0, bytesRead);
     }
-    from.close();
-
-    to.flush();
-    to.close();
-
     //noinspection ResultOfMethodCallIgnored
     targetFile.setLastModified(sourceFile.lastModified());
     //noinspection ResultOfMethodCallIgnored
     targetFile.setExecutable(sourceFile.canExecute());
+    }
   }
 
 
@@ -218,13 +213,15 @@ static public void saveFile(String text, File file) throws IOException {
                             file.getAbsolutePath());
     }
     // Could use saveStrings(), but we wouldn't be able to checkError()
-    PrintWriter writer = PApplet.createWriter(temp);
-    for (String line : lines) {
-      writer.println(line);
-    }
-    boolean error = writer.checkError();  // calls flush()
-    writer.close();  // attempt to close regardless
-    if (error) {
+      boolean error;
+      try (PrintWriter writer = PApplet.createWriter(temp)) {
+          for (String line : lines) {
+              writer.println(line);
+          }
+          // calls flush()
+          error = writer.checkError();
+      }
+      if (error) {
       throw new IOException("Error while trying to save " + file);
     }
 
@@ -589,7 +586,7 @@ static public StringList packageListFromClassPath(String path) {
 
     for (String piece : pieces) {
       //System.out.println("checking piece '" + pieces[i] + "'");
-      if (piece.length() != 0) {
+      if (!piece.isEmpty()) {
         if (piece.toLowerCase().endsWith(".jar") ||
           piece.toLowerCase().endsWith(".zip")) {
           //System.out.println("checking " + pieces[i]);
@@ -623,8 +620,7 @@ static public StringList packageListFromClassPath(String path) {
 
 
   static private void packageListFromZip(String filename, StringList list) {
-    try {
-      ZipFile file = new ZipFile(filename);
+    try (ZipFile file = new ZipFile(filename);) {
       Enumeration<?> entries = file.entries();
       while (entries.hasMoreElements()) {
         ZipEntry entry = (ZipEntry) entries.nextElement();
@@ -643,7 +639,6 @@ static private void packageListFromZip(String filename, StringList list) {
           }
         }
       }
-      file.close();
     } catch (IOException e) {
       System.err.println("Ignoring " + filename + " (" + e.getMessage() + ")");
       //e.printStackTrace();
@@ -688,9 +683,7 @@ static private void packageListFromFolder(File dir, String sofar,
    * Ignores (does not extract) any __MACOSX files from macOS archives.
    */
   static public void unzip(File zipFile, File dest) throws IOException {
-    FileInputStream fis = new FileInputStream(zipFile);
-    CheckedInputStream checksum = new CheckedInputStream(fis, new Adler32());
-    ZipInputStream zis = new ZipInputStream(new BufferedInputStream(checksum));
+    try (ZipInputStream zis = new ZipInputStream( new BufferedInputStream( new CheckedInputStream( new FileInputStream(zipFile), new Adler32())))) {
     ZipEntry entry;
     while ((entry = zis.getNextEntry()) != null) {
       final String name = entry.getName();
@@ -710,25 +703,26 @@ static public void unzip(File zipFile, File dest) throws IOException {
       }
     }
   }
+  }
 
 
   static protected void unzipEntry(ZipInputStream zin, File f) throws IOException {
-    FileOutputStream out = new FileOutputStream(f);
-    byte[] b = new byte[512];
-    int len;
-    while ((len = zin.read(b)) != -1) {
-      out.write(b, 0, len);
-    }
-    out.flush();
-    out.close();
+      try (FileOutputStream out = new FileOutputStream(f)) {
+          byte[] b = new byte[512];
+          int len;
+          while ((len = zin.read(b)) != -1) {
+              out.write(b, 0, len);
+          }
+          out.flush();
+      }
   }
 
 
   static public byte[] gzipEncode(byte[] what) throws IOException {
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
-    GZIPOutputStream output = new GZIPOutputStream(baos);
-    PApplet.saveStream(output, new ByteArrayInputStream(what));
-    output.close();
+    try (GZIPOutputStream output = new GZIPOutputStream(baos);) {
+      PApplet.saveStream(output, new ByteArrayInputStream(what));
+    }
     return baos.toByteArray();
   }