Refactor lines into their own package.  I'm planning to have a class for each line type, so each one, when constructed with a line of input, will parse out what it needs from the contents.
M src/main/java/com/ajtjp/geminiclient/GeminiClient.java +2 -0
@@ 1,5 1,7 @@ 
 package com.ajtjp.geminiclient;
 
+import com.ajtjp.geminiclient.lines.LineType;
+import com.ajtjp.geminiclient.lines.GeminiLine;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;

          
M src/main/java/com/ajtjp/geminiclient/GeminiDocument.java +1 -0
@@ 1,5 1,6 @@ 
 package com.ajtjp.geminiclient;
 
+import com.ajtjp.geminiclient.lines.GeminiLine;
 import java.util.ArrayList;
 import java.util.List;
 

          
M src/main/java/com/ajtjp/geminiclient/Main.java +2 -0
@@ 1,5 1,7 @@ 
 package com.ajtjp.geminiclient;
 
+import com.ajtjp.geminiclient.lines.LineType;
+import com.ajtjp.geminiclient.lines.GeminiLine;
 import java.io.IOException;
 import java.util.List;
 

          
M src/main/java/com/ajtjp/geminiclient/GeminiLine.java => src/main/java/com/ajtjp/geminiclient/lines/GeminiLine.java +1 -1
@@ 1,4 1,4 @@ 
-package com.ajtjp.geminiclient;
+package com.ajtjp.geminiclient.lines;
 
 public class GeminiLine {
     public LineType type;

          
M src/main/java/com/ajtjp/geminiclient/LineType.java => src/main/java/com/ajtjp/geminiclient/lines/LineType.java +1 -1
@@ 1,4 1,4 @@ 
-package com.ajtjp.geminiclient;
+package com.ajtjp.geminiclient.lines;
 
 public enum LineType {
     TEXT,