Close all streams for TOFU known hosts file

Author: lutovich

driver/src/main/java/org/neo4j/driver/internal/security/TrustOnFirstUseTrustManager.java

@@ -82,22 +82,23 @@ private void load() throws IOException
 
         assertKnownHostFileReadable();
 
-        BufferedReader reader = new BufferedReader( new FileReader( knownHosts ) );
-        String line;
-        while ( (line = reader.readLine()) != null )
+        try ( BufferedReader reader = new BufferedReader( new FileReader( knownHosts ) ) )
         {
-            if ( (!line.trim().startsWith( "#" )) )
+            String line;
+            while ( (line = reader.readLine()) != null )
             {
-                String[] strings = line.split( " " );
-                if ( strings[0].trim().equals( serverId ) )
+                if ( (!line.trim().startsWith( "#" )) )
                 {
-                    // load the certificate
-                    fingerprint = strings[1].trim();
-                    return;
+                    String[] strings = line.split( " " );
+                    if ( strings[0].trim().equals( serverId ) )
+                    {
+                        // load the certificate
+                        fingerprint = strings[1].trim();
+                        return;
+                    }
                 }
             }
         }
-        reader.close();
     }
 
     /**
@@ -113,10 +114,11 @@ private void saveTrustedHost( String fingerprint ) throws IOException
         createKnownCertFileIfNotExists();
 
         assertKnownHostFileWritable();
-        BufferedWriter writer = new BufferedWriter( new FileWriter( knownHosts, true ) );
-        writer.write( serverId + " " + this.fingerprint );
-        writer.newLine();
-        writer.close();
+        try ( BufferedWriter writer = new BufferedWriter( new FileWriter( knownHosts, true ) ) )
+        {
+            writer.write( serverId + " " + this.fingerprint );
+            writer.newLine();
+        }
     }
 
 

driver/src/test/java/org/neo4j/driver/internal/security/TrustOnFirstUseTrustManagerTest.java

@@ -68,10 +68,11 @@ void setUp() throws Throwable
         knownCertificate = mock( X509Certificate.class );
         when( knownCertificate.getEncoded() ).thenReturn( "certificate".getBytes( UTF_8 ) );
 
-        PrintWriter writer = new PrintWriter( knownCertsFile );
-        writer.println( " # I am a comment." );
-        writer.println( knownServer + " " + fingerprint( knownCertificate ) );
-        writer.close();
+        try ( PrintWriter writer = new PrintWriter( knownCertsFile ) )
+        {
+            writer.println( " # I am a comment." );
+            writer.println( knownServer + " " + fingerprint( knownCertificate ) );
+        }
     }
 
     @AfterEach
@@ -86,8 +87,7 @@ void shouldLoadExistingCert() throws Throwable
         // Given
         BoltServerAddress knownServerAddress = new BoltServerAddress( knownServerIp, knownServerPort );
         Logger logger = mock(Logger.class);
-        TrustOnFirstUseTrustManager manager =
-                new TrustOnFirstUseTrustManager( knownServerAddress, knownCertsFile, logger );
+        TrustOnFirstUseTrustManager manager = new TrustOnFirstUseTrustManager( knownServerAddress, knownCertsFile, logger );
 
         X509Certificate wrongCertificate = mock( X509Certificate.class );
         when( wrongCertificate.getEncoded() ).thenReturn( "fake certificate".getBytes() );
@@ -116,14 +116,14 @@ void shouldSaveNewCert() throws Throwable
         verify( logger ).info( "Adding %s as known and trusted certificate for %s.", fingerprint, "1.2.3.4:200" );
 
         // And the file should contain the right info
-        Scanner reader = new Scanner( knownCertsFile );
-
-        String line;
-        line = nextLine( reader );
-        assertEquals( knownServer + " " + fingerprint, line );
-        assertTrue( reader.hasNextLine() );
-        line = nextLine( reader );
-        assertEquals( knownServerIp + ":" + newPort + " " + fingerprint, line );
+        try ( Scanner reader = new Scanner( knownCertsFile ) )
+        {
+            String line1 = nextLine( reader );
+            assertEquals( knownServer + " " + fingerprint, line1 );
+            assertTrue( reader.hasNextLine() );
+            String line2 = nextLine( reader );
+            assertEquals( knownServerIp + ":" + newPort + " " + fingerprint, line2 );
+        }
     }
 
     private String nextLine( Scanner reader )