Use try-with-resources.

src/test/java/org/apache/commons/csv/CSVPrinterTest.java

@@ -282,9 +282,8 @@ public class CSVPrinterTest {
     @Test
     public void testCloseWithFlushOn() throws IOException {
         try (final Writer writer = mock(Writer.class)) {
-            final CSVFormat csvFormat = CSVFormat.DEFAULT;
             @SuppressWarnings("resource")
-            final CSVPrinter csvPrinter = new CSVPrinter(writer, csvFormat);
+            final CSVPrinter csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT);
             csvPrinter.close(true);
             verify(writer, times(1)).flush();
         }
@@ -328,8 +327,8 @@ public class CSVPrinterTest {
     @Test
     public void testCSV259() throws IOException {
         final StringWriter sw = new StringWriter();
-        final Reader reader = new FileReader("src/test/resources/org/apache/commons/csv/CSV-259/sample.txt");
-        try (final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT.withEscape('!').withQuote(null))) {
+        try (final Reader reader = new FileReader("src/test/resources/org/apache/commons/csv/CSV-259/sample.txt");
+                final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT.withEscape('!').withQuote(null))) {
             printer.print(reader);
             assertEquals("x!,y!,z", sw.toString());
         }
@@ -624,12 +623,12 @@ public class CSVPrinterTest {
         try (final Connection connection = getH2Connection()) {
             setUpTable(connection);
             try (final Statement stmt = connection.createStatement();
-                    final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT)) {
-                printer.printRecords(stmt.executeQuery("select ID, NAME, TEXT from TEST"));
+                    final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT);
+                    final ResultSet resultSet = stmt.executeQuery("select ID, NAME, TEXT from TEST");) {
+                printer.printRecords(resultSet);
             }
         }
-        assertEquals("1,r1,\"long text 1\"" + recordSeparator + "2,r2,\"" + longText2 + "\"" + recordSeparator,
-                sw.toString());
+        assertEquals("1,r1,\"long text 1\"" + recordSeparator + "2,r2,\"" + longText2 + "\"" + recordSeparator, sw.toString());
     }
 
     @Test

src/test/java/org/apache/commons/csv/issues/JiraCsv167Test.java

@@ -20,7 +20,6 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 
@@ -83,7 +82,6 @@ public class JiraCsv167Test {
     }
 
     private Reader getTestInput() {
-        final InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("org/apache/commons/csv/csv-167/sample1.csv");
-        return new InputStreamReader(is);
+        return new InputStreamReader(ClassLoader.getSystemClassLoader().getResourceAsStream("org/apache/commons/csv/csv-167/sample1.csv"));
     }
 }

src/test/java/org/apache/commons/csv/issues/JiraCsv211Test.java

@@ -37,12 +37,12 @@ public class JiraCsv211Test {
         assertEquals("ID\tName\tCountry\tAge\r\n1\tJane Doe\tUSA\t", formatted);
 
         final CSVFormat parseFormat = CSVFormat.DEFAULT.withDelimiter('\t').withFirstRecordAsHeader();
-        final CSVParser parser = parseFormat.parse(new StringReader(formatted));
+        try (final CSVParser parser = parseFormat.parse(new StringReader(formatted))) {
             for (final CSVRecord record : parser) {
                 assertEquals("1", record.get(0));
                 assertEquals("Jane Doe", record.get(1));
                 assertEquals("USA", record.get(2));
                 assertEquals("", record.get(3));
             }
-    }
+        }}
 }

src/test/java/org/apache/commons/csv/issues/JiraCsv247Test.java

@@ -65,17 +65,18 @@ public class JiraCsv247Test {
     public void testHeadersMissingThrowsWhenNotAllowingMissingColumnNames() throws Exception {
         final CSVFormat format = CSVFormat.DEFAULT.withHeader();
 
-        assertFalse(format.getAllowMissingColumnNames(),
-            "By default we should not allow missing column names");
+        assertFalse(format.getAllowMissingColumnNames(), "By default we should not allow missing column names");
 
         assertThrows(IllegalArgumentException.class, () -> {
-            final Reader in = new StringReader("a,,c,d,e\n1,2,3,4,5\nv,w,x,y,z");
+            try (final Reader in = new StringReader("a,,c,d,e\n1,2,3,4,5\nv,w,x,y,z")) {
                 format.parse(in);
+            }
         }, "1 missing column header is not allowed");
 
         assertThrows(IllegalArgumentException.class, () -> {
-            final Reader in = new StringReader("a,,c,d,\n1,2,3,4,5\nv,w,x,y,z");
+            try (final Reader in = new StringReader("a,,c,d,\n1,2,3,4,5\nv,w,x,y,z")) {
                 format.parse(in);
+            }
         }, "2+ missing column headers is not allowed!");
     }
 }

src/test/java/org/apache/commons/csv/perf/PerformanceTest.java

@@ -94,11 +94,13 @@ public class PerformanceTest {
 
     public long testParseBigFile(final boolean traverseColumns) throws Exception {
         final long startMillis = System.currentTimeMillis();
-        final long count = this.parse(this.createBufferedReader(), traverseColumns);
+        try (final BufferedReader reader = this.createBufferedReader()) {
+            final long count = this.parse(reader, traverseColumns);
             final long totalMillis = System.currentTimeMillis() - startMillis;
             this.println(String.format("File parsed in %,d milliseconds with Commons CSV: %,d lines.", totalMillis, count));
             return totalMillis;
         }
+    }
 
     @Test
     public void testParseBigFileRepeat() throws Exception {