Add basic game config grabber/logic to check for an update. I guess this works.

src/main/java/net/runelite/deob/updater/GameConfig.java

@@ -0,0 +1,74 @@
+package net.runelite.deob.updater;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.HashMap;
+import java.util.Map;
+
+public class GameConfig
+{
+	private static final String URL = "http://192.168.1.2/rs/jav_config.ws";
+	//private static final String URL = "http://oldschool.runescape.com/jav_config.ws"; // https redirects to rs3
+
+	private final Map<String, String> properties = new HashMap<>(),
+		appletProperties = new HashMap<>();
+
+	public void fetch() throws IOException
+	{
+		URLConnection conn = new URL(URL).openConnection();
+		try (BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream())))
+		{
+			String str;
+
+			while ((str = in.readLine()) != null)
+			{
+				int idx = str.indexOf('=');
+
+				if (idx == -1)
+					continue;
+
+				String s = str.substring(0, idx);
+
+				if (s.equals("param"))
+				{
+					str = str.substring(idx + 1);
+					idx = str.indexOf('=');
+					s = str.substring(0, idx);
+
+					appletProperties.put(s, str.substring(idx + 1));
+				}
+				else if (s.equals("msg"))
+				{
+					// ignore
+				}
+				else
+				{
+					properties.put(s, str.substring(idx + 1));
+				}
+			}
+		}
+	}
+
+	public String getProperty(String name)
+	{
+		return properties.get(name);
+	}
+
+	public Map<String, String> getProperties()
+	{
+		return properties;
+	}
+
+	public String getAppletProperty(String name)
+	{
+		return appletProperties.get(name);
+	}
+
+	public Map<String, String> getAppletProperties()
+	{
+		return appletProperties;
+	}
+}

src/main/java/net/runelite/deob/updater/GameConfigUpdateDetector.java

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+package net.runelite.deob.updater;
+
+import com.google.common.base.Strings;
+
+public class GameConfigUpdateDetector
+{
+	private final GameConfig g1, g2;
+
+	public GameConfigUpdateDetector(GameConfig g1, GameConfig g2)
+	{
+		this.g1 = g1;
+		this.g2 = g2;
+	}
+
+	public boolean hasUpdated()
+	{
+		// between game updatesthe parameters are scrambled, so detect when that happens.
+		// normally only one parameter changes, which is some integer value (+ the world)
+		//
+		// N.B. my other idea is to compare content-length in HEAD requests for the gamepack.
+		// the httpd doesn't support if-match and does not etag anything, and the last-modified time
+		// appears to be constant NOW-1 week (it moves per request)
+		
+		int differences = 0;
+
+		for (String key : g1.getProperties().keySet())
+		{
+			String value = g1.getAppletProperty(key), otherValue = g2.getAppletProperty(value);
+
+			if (!Strings.nullToEmpty(value).equals(Strings.nullToEmpty(otherValue)))
+				++differences;
+		}
+
+		return differences > 2; // random number, world
+	}
+}

src/test/java/net/runelite/deob/updater/GameConfigTest.java

@@ -0,0 +1,17 @@
+package net.runelite.deob.updater;
+
+import java.io.IOException;
+import org.junit.Test;
+
+public class GameConfigTest
+{
+	@Test
+	public void testGetAppletProperties() throws IOException
+	{
+		GameConfig config = new GameConfig();
+		config.fetch();
+		System.out.println(config.getProperties());
+		System.out.println(config.getAppletProperties());
+	}
+
+}

src/test/java/net/runelite/deob/updater/GameConfigUpdateDetectorTest.java

@@ -0,0 +1,20 @@
+package net.runelite.deob.updater;
+
+import java.io.IOException;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class GameConfigUpdateDetectorTest
+{
+	@Test
+	public void testHasUpdated() throws IOException
+	{
+		GameConfig c1 = new GameConfig(), c2 = new GameConfig();
+		c1.fetch();
+		c2.fetch();
+
+		GameConfigUpdateDetector gcu = new GameConfigUpdateDetector(c1, c2);
+		Assert.assertFalse(gcu.hasUpdated());
+	}
+
+}