diff --git a/runtime/Java/src/org/antlr/v4/runtime/ANTLRFileStream.java b/runtime/Java/src/org/antlr/v4/runtime/ANTLRFileStream.java
index ede83eb263..18a7c8e427 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/ANTLRFileStream.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/ANTLRFileStream.java
@@ -15,6 +15,7 @@
  *
  * @deprecated as of 4.7 Please use {@link CharStreams} interface.
  */
+@Deprecated
 public class ANTLRFileStream extends ANTLRInputStream {
 	protected String fileName;
 
diff --git a/runtime/Java/src/org/antlr/v4/runtime/ANTLRInputStream.java b/runtime/Java/src/org/antlr/v4/runtime/ANTLRInputStream.java
index f71a62de36..0fbca01032 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/ANTLRInputStream.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/ANTLRInputStream.java
@@ -22,6 +22,7 @@
  *
  * @deprecated as of 4.7 Please use {@link CharStreams} interface.
  */
+@Deprecated
 public class ANTLRInputStream implements CharStream {
     public static final int READ_BUFFER_SIZE = 1024;
    	public static final int INITIAL_BUFFER_SIZE = 1024;
diff --git a/runtime/Java/src/org/antlr/v4/runtime/CommonToken.java b/runtime/Java/src/org/antlr/v4/runtime/CommonToken.java
index a34020f160..42ff55aa99 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/CommonToken.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/CommonToken.java
@@ -261,8 +261,7 @@ public String toString() {
 		return toString(null);
 	}
 
-	public String toString(Recognizer r) {
-
+	public String toString(Recognizer<?, ?> r) {
 		String channelStr = "";
 		if ( channel>0 ) {
 			channelStr=",channel="+channel;
diff --git a/runtime/Java/src/org/antlr/v4/runtime/atn/ATNDeserializer.java b/runtime/Java/src/org/antlr/v4/runtime/atn/ATNDeserializer.java
index 0ebcdeb31e..7ce78f1532 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/atn/ATNDeserializer.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/atn/ATNDeserializer.java
@@ -789,8 +789,7 @@ protected LexerAction lexerActionFactory(LexerActionType type, int data1, int da
 			return new LexerTypeAction(data1);
 
 		default:
-			String message = String.format(Locale.getDefault(), "The specified lexer action type %d is not valid.", type);
-			throw new IllegalArgumentException(message);
+			throw new IllegalArgumentException(String.format(Locale.getDefault(), "The specified lexer action type %s is not valid.", type));
 		}
 	}
 }
diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/NotNull.java b/runtime/Java/src/org/antlr/v4/runtime/misc/NotNull.java
index 78052918af..216c938578 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/NotNull.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/NotNull.java
@@ -17,5 +17,6 @@
 @Documented
 @Retention(RetentionPolicy.CLASS)
 @Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.LOCAL_VARIABLE})
+@Deprecated
 public @interface NotNull {
 }
diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/TestRig.java b/runtime/Java/src/org/antlr/v4/runtime/misc/TestRig.java
index 2be97840a2..3f91539b43 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/TestRig.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/TestRig.java
@@ -14,6 +14,7 @@
  *  @deprecated
  *  @since 4.5.1
  */
+@Deprecated
 public class TestRig {
 	public static void main(String[] args) {
 		try {
diff --git a/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java b/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
index 406d2afbec..bf6531b7aa 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
@@ -185,6 +185,7 @@ public static List<ParseTree> getDescendants(ParseTree t) {
 	}
 
 	/** @deprecated */
+  @Deprecated
 	public static List<ParseTree> descendants(ParseTree t) {
 		return getDescendants(t);
 	}
diff --git a/tool/src/org/antlr/v4/codegen/target/GoTarget.java b/tool/src/org/antlr/v4/codegen/target/GoTarget.java
index 2d1f831e52..f4d69c3d8e 100644
--- a/tool/src/org/antlr/v4/codegen/target/GoTarget.java
+++ b/tool/src/org/antlr/v4/codegen/target/GoTarget.java
@@ -134,7 +134,9 @@ public String encodeIntAsCharEscape(int v) {
 
 	@Override
 	public int getSerializedATNSegmentLimit() {
-		return 2 ^ 31;
+		// 65535 is the class file format byte limit for a UTF-8 encoded string literal
+		// 3 is the maximum number of bytes it takes to encode a value in the range 0-0xFFFF
+		return 65535 / 3;
 	}
 
 	@Override
diff --git a/tool/src/org/antlr/v4/misc/MutableInt.java b/tool/src/org/antlr/v4/misc/MutableInt.java
index 007f4c21eb..5ca76f5777 100644
--- a/tool/src/org/antlr/v4/misc/MutableInt.java
+++ b/tool/src/org/antlr/v4/misc/MutableInt.java
@@ -6,7 +6,7 @@
 
 package org.antlr.v4.misc;
 
-public class MutableInt extends Number implements Comparable<Number> {
+public class MutableInt extends Number implements Comparable<MutableInt> {
 	public int v;
 
 	public MutableInt(int v) { this.v = v; }
@@ -19,7 +19,7 @@ public boolean equals(Object o) {
 
 	@Override public int hashCode() { return v; }
 
-	@Override public int compareTo(Number o) { return v-o.intValue(); }
+	@Override public int compareTo(MutableInt o) { return v-o.intValue(); }
 	@Override public int intValue() { return v; }
 	@Override public long longValue() { return v; }
 	@Override public float floatValue() { return v; }
diff --git a/tool/src/org/antlr/v4/tool/ErrorManager.java b/tool/src/org/antlr/v4/tool/ErrorManager.java
index 74212665fd..9f1c65afab 100644
--- a/tool/src/org/antlr/v4/tool/ErrorManager.java
+++ b/tool/src/org/antlr/v4/tool/ErrorManager.java
@@ -61,7 +61,7 @@ public ST getMessageTemplate(ANTLRMessage msg) {
 		}
 		if (msg.fileName != null) {
 			String displayFileName = msg.fileName;
-			if (format.equals("antlr")) {
+			if (formatName.equals("antlr")) {
 				// Don't show path to file in messages in ANTLR format;
 				// they're too long.
 				File f = new File(msg.fileName);
@@ -206,6 +206,8 @@ public void emit(ErrorType etype, ANTLRMessage msg) {
 				errors++;
 				tool.error(msg);
 				break;
+      default:
+        break;
 		}
 		errorTypes.add(etype);
 	}