drop check on java version

as java8 is a compile time requirement, the checks for jvm version
before java7 makes no sense anymore.

Remove unused JdkVersion class.

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>

extras/tls-sni/src/main/java/org/glassfish/grizzly/sni/SNIFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -38,7 +38,6 @@
 import org.glassfish.grizzly.ssl.SSLEngineConfigurator;
 import org.glassfish.grizzly.ssl.SSLFilter;
 import org.glassfish.grizzly.utils.Charsets;
-import org.glassfish.grizzly.utils.JdkVersion;
 
 /**
  * TLS Server Name Indication (SNI) {@link Filter} implementation. This filter supports SNI extension on both client and
@@ -57,7 +56,6 @@
  */
 public class SNIFilter extends SSLFilter {
     private static final Logger LOGGER = Grizzly.logger(SNIFilter.class);
-    private static final boolean JDK7_OR_HIGHER = JdkVersion.getJdkVersion().compareTo(JdkVersion.parseVersion("1.7")) >= 0;
 
     private static final byte HANDSHAKE_TYPE = 0x16;
     private static final int MIN_TLS_VERSION = 0x0301;
@@ -125,10 +123,6 @@ public SNIClientConfigResolver getClientSSLConfigResolver() {
      * @param resolver
      */
     public void setClientSSLConfigResolver(final SNIClientConfigResolver resolver) {
-        if (!JDK7_OR_HIGHER) {
-            LOGGER.warning("Client side SNI support requires JDK 1.7+");
-        }
-
         this.clientResolver = resolver;
     }
 
@@ -141,10 +135,6 @@ protected SSLTransportFilterWrapper createOptimizedTransportFilter(final Transpo
 
     @Override
     public NextAction handleConnect(final FilterChainContext ctx) throws IOException {
-        if (!JDK7_OR_HIGHER) {
-            return super.handleConnect(ctx);
-        }
-
         // new client-side connection
         final Connection c = ctx.getConnection();
 

extras/tls-sni/src/test/java/org/glassfish/grizzly/sni/SNITest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2017 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -34,7 +34,6 @@
 import org.glassfish.grizzly.ssl.SSLContextConfigurator;
 import org.glassfish.grizzly.ssl.SSLEngineConfigurator;
 import org.glassfish.grizzly.utils.Futures;
-import org.glassfish.grizzly.utils.JdkVersion;
 import org.glassfish.grizzly.utils.StringFilter;
 import org.junit.Test;
 
@@ -48,21 +47,15 @@
 @SuppressWarnings("unchecked")
 public class SNITest {
     public static final int PORT = 19283;
-    private static final boolean JDK7_OR_HIGHER = JdkVersion.getJdkVersion()
-            .compareTo(JdkVersion.parseVersion("1.7")) >= 0;
-
+
     @Test
     public void testClientServerSNI() throws Exception {
         final String sniHostValue = "sni-test.com";
         final String msg = "Hello world!";
 
         final Attribute<String> sniHostAttr =
                 Grizzly.DEFAULT_ATTRIBUTE_BUILDER.createAttribute("sni-host-attr");
-
-        if (!JDK7_OR_HIGHER) {
-            return;
-        }
-
+
         final SSLEngineConfigurator sslServerEngineConfig = 
                     new SSLEngineConfigurator(
                             createSSLContextConfigurator().createSSLContext(),

modules/grizzly/src/main/java/org/glassfish/grizzly/nio/transport/UDPNIOConnection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -42,7 +42,6 @@
 import org.glassfish.grizzly.nio.SelectorRunner;
 import org.glassfish.grizzly.utils.Exceptions;
 import org.glassfish.grizzly.utils.Holder;
-import org.glassfish.grizzly.utils.JdkVersion;
 import org.glassfish.grizzly.utils.NullaryFunction;
 
 /**
@@ -65,28 +64,25 @@ public class UDPNIOConnection extends NIOConnection {
     private static final Method MK_UNBLOCK_METHOD;
 
     static {
-        JdkVersion jdkVersion = JdkVersion.getJdkVersion();
-        JdkVersion minimumVersion = JdkVersion.parseVersion("1.7.0");
 
         boolean isInitialized = false;
         Method join = null, joinWithSource = null, mkGetNetworkInterface = null, mkGetSourceAddress = null, mkDrop = null, mkBlock = null, mkUnblock = null;
-        if (minimumVersion.compareTo(jdkVersion) <= 0) { // If JDK version is >= 1.7
-            try {
-                join = DatagramChannel.class.getMethod("join", InetAddress.class, NetworkInterface.class);
-                joinWithSource = DatagramChannel.class.getMethod("join", InetAddress.class, NetworkInterface.class, InetAddress.class);
 
-                final Class membershipKeyClass = loadClass("java.nio.channels.MembershipKey");
+        try {
+            join = DatagramChannel.class.getMethod("join", InetAddress.class, NetworkInterface.class);
+            joinWithSource = DatagramChannel.class.getMethod("join", InetAddress.class, NetworkInterface.class, InetAddress.class);
 
-                mkGetNetworkInterface = membershipKeyClass.getDeclaredMethod("networkInterface");
-                mkGetSourceAddress = membershipKeyClass.getDeclaredMethod("sourceAddress");
-                mkDrop = membershipKeyClass.getDeclaredMethod("drop");
+            final Class membershipKeyClass = loadClass("java.nio.channels.MembershipKey");
 
-                mkBlock = membershipKeyClass.getDeclaredMethod("block", InetAddress.class);
-                mkUnblock = membershipKeyClass.getDeclaredMethod("unblock", InetAddress.class);
-                isInitialized = true;
-            } catch (Throwable t) {
-                LOGGER.log(Level.WARNING, LogMessages.WARNING_GRIZZLY_CONNECTION_UDPMULTICASTING_EXCEPTIONE(), t);
-            }
+            mkGetNetworkInterface = membershipKeyClass.getDeclaredMethod("networkInterface");
+            mkGetSourceAddress = membershipKeyClass.getDeclaredMethod("sourceAddress");
+            mkDrop = membershipKeyClass.getDeclaredMethod("drop");
+
+            mkBlock = membershipKeyClass.getDeclaredMethod("block", InetAddress.class);
+            mkUnblock = membershipKeyClass.getDeclaredMethod("unblock", InetAddress.class);
+            isInitialized = true;
+        } catch (Throwable t) {
+            LOGGER.log(Level.WARNING, LogMessages.WARNING_GRIZZLY_CONNECTION_UDPMULTICASTING_EXCEPTIONE(), t);
         }
 
         if (isInitialized) {

modules/grizzly/src/main/java/org/glassfish/grizzly/ssl/SSLFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -42,7 +42,6 @@
 import org.glassfish.grizzly.filterchain.FilterChainContext.Operation;
 import org.glassfish.grizzly.filterchain.NextAction;
 import org.glassfish.grizzly.utils.Exceptions;
-import org.glassfish.grizzly.utils.JdkVersion;
 
 /**
  * SSL {@link Filter} to operate with SSL encrypted data.
@@ -51,7 +50,6 @@
  */
 public class SSLFilter extends SSLBaseFilter {
     private static final Logger LOGGER = Grizzly.logger(SSLFilter.class);
-    private static final boolean IS_JDK7_OR_HIGHER = JdkVersion.getJdkVersion().compareTo("1.7.0") >= 0;
 
     private final Attribute<SSLHandshakeContext> handshakeContextAttr;
     private final SSLEngineConfigurator clientSSLEngineConfigurator;
@@ -268,8 +266,7 @@ protected Buffer doHandshakeStep(final SSLConnectionContext sslCtx, final Filter
 
     protected SSLEngine createClientSSLEngine(final SSLConnectionContext sslCtx, final SSLEngineConfigurator sslEngineConfigurator) {
 
-        return IS_JDK7_OR_HIGHER ? sslEngineConfigurator.createSSLEngine(HostNameResolver.getPeerHostName(sslCtx.getConnection()), -1)
-                : sslEngineConfigurator.createSSLEngine();
+        return sslEngineConfigurator.createSSLEngine(HostNameResolver.getPeerHostName(sslCtx.getConnection()), -1);
     }
 
     // ----------------------------------------------------------- Inner Classes

modules/http-server/src/main/java/org/glassfish/grizzly/http/server/ServerFilterConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -19,7 +19,6 @@
 import java.nio.charset.Charset;
 
 import org.glassfish.grizzly.Grizzly;
-import org.glassfish.grizzly.utils.JdkVersion;
 
 /**
  * {@link HttpServerFilter} configuration.
@@ -482,7 +481,7 @@ public void setSessionManager(SessionManager sessionManager) {
 
     private void configureSendFileSupport() {
 
-        if (System.getProperty("os.name").equalsIgnoreCase("linux") && !linuxSendFileSupported() || System.getProperty("os.name").equalsIgnoreCase("HP-UX")) {
+        if (System.getProperty("os.name").equalsIgnoreCase("HP-UX")) {
             sendFileEnabled = false;
         }
 
@@ -493,10 +492,4 @@ private void configureSendFileSupport() {
 
     }
 
-    private static boolean linuxSendFileSupported() {
-        JdkVersion jdkVersion = JdkVersion.getJdkVersion();
-        JdkVersion minimumVersion = JdkVersion.parseVersion("1.6.0_18");
-        return minimumVersion.compareTo(jdkVersion) <= 0;
-    }
-
 }

samples/framework-samples/src/main/java/org/glassfish/grizzly/samples/udpmulticast/MulticastChat.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Distribution License v. 1.0, which is available at
@@ -25,7 +25,6 @@
 import org.glassfish.grizzly.nio.transport.UDPNIOConnection;
 import org.glassfish.grizzly.nio.transport.UDPNIOTransport;
 import org.glassfish.grizzly.nio.transport.UDPNIOTransportBuilder;
-import org.glassfish.grizzly.utils.JdkVersion;
 import org.glassfish.grizzly.utils.StringFilter;
 
 /**
@@ -96,14 +95,6 @@ public static void main(String[] args) throws Exception {
     }
 
     private void run() throws Exception {
-        // Check if current JDK version is higher or equals to 1.7.0
-        final JdkVersion jdkVersion = JdkVersion.getJdkVersion();
-        final JdkVersion minimumVersion = JdkVersion.parseVersion("1.7.0");
-
-        if (minimumVersion.compareTo(jdkVersion) > 0) { // If JDK version is >= 1.7
-            System.out.println("Sample requires JDK 1.7+");
-            System.exit(1);
-        }
 
         // Build FilterChain to parse incoming UDP packets and print to System.out
         final FilterChain filterChain = FilterChainBuilder.stateless()