diff --git a/core/src/main/java/org/jruby/RubyBignum.java b/core/src/main/java/org/jruby/RubyBignum.java
index f3ebe34d31c..65b673d04b8 100644
--- a/core/src/main/java/org/jruby/RubyBignum.java
+++ b/core/src/main/java/org/jruby/RubyBignum.java
@@ -1028,7 +1028,7 @@ private boolean float_eq(ThreadContext context, RubyFloat y) {
 
         // compare as integers to avoid precision loss
         IRubyObject rel = op_cmp(context, newBignorm(context.runtime, yd));
-        return rel instanceof RubyFixnum fix && fix.getLongValue() == 0;
+        return rel instanceof RubyFixnum fix && fix.getValue() == 0;
     }
 
     @Override
diff --git a/core/src/main/java/org/jruby/RubyInteger.java b/core/src/main/java/org/jruby/RubyInteger.java
index ddd808561e7..0b28e8781ee 100644
--- a/core/src/main/java/org/jruby/RubyInteger.java
+++ b/core/src/main/java/org/jruby/RubyInteger.java
@@ -460,7 +460,7 @@ public static RubyString singleCharString(Ruby runtime, byte b, RubyClass meta,
 
         if (bytes == null) {
             // just share byte array
-            return RubyString.newStringShared(runtime, SINGLE_CHAR_BYTES[ub], enc);
+            return RubyString.newStringShared(runtime, SINGLE_CHAR_BYTES[ub], 0, SINGLE_CHAR_BYTES[ub].length, enc);
         }
 
         // use shared for cached bytelists
diff --git a/core/src/main/java/org/jruby/RubyModule.java b/core/src/main/java/org/jruby/RubyModule.java
index cc8406d585d..be5a93f6a49 100644
--- a/core/src/main/java/org/jruby/RubyModule.java
+++ b/core/src/main/java/org/jruby/RubyModule.java
@@ -3225,7 +3225,7 @@ public int hashCode() {
         if (hash.isBuiltin(this)) return id;
 
         // we truncate for Java hashcode
-        return (int) hash.call(context, this, this).convertToInteger().getLongValue();
+        return (int) hash.call(context, this, this).convertToInteger().asLong(context);
     }
 
     @JRubyMethod(name = "hash")
diff --git a/core/src/main/java/org/jruby/RubyRegexp.java b/core/src/main/java/org/jruby/RubyRegexp.java
index 6fa8e0825a2..db13a9b8b53 100755
--- a/core/src/main/java/org/jruby/RubyRegexp.java
+++ b/core/src/main/java/org/jruby/RubyRegexp.java
@@ -1586,7 +1586,7 @@ public IRubyObject named_captures(ThreadContext context) {
             for (int idx = 0; idx<backrefs.length; idx++) {
                 ary.storeInternal(context, idx, asFixnum(context, backrefs[idx]));
             }
-            RubyString name = RubyString.newStringShared(context.runtime, e.name, e.nameP, e.nameEnd - e.nameP);
+            RubyString name = RubyString.newStringShared(context.runtime, e.name, e.nameP, e.nameEnd - e.nameP, ASCIIEncoding.INSTANCE);
             hash.fastASet(name.freeze(context), ary);
         }
         return hash;
diff --git a/core/src/main/java/org/jruby/runtime/marshal/MarshalDumper.java b/core/src/main/java/org/jruby/runtime/marshal/MarshalDumper.java
index cb5d49fafeb..27110e8076b 100644
--- a/core/src/main/java/org/jruby/runtime/marshal/MarshalDumper.java
+++ b/core/src/main/java/org/jruby/runtime/marshal/MarshalDumper.java
@@ -71,8 +71,8 @@
 import java.util.function.BiConsumer;
 
 import static org.jruby.RubyBasicObject.getMetaClass;
-import static org.jruby.api.Access.stringClass;
 import static org.jruby.api.Convert.*;
+import static org.jruby.api.Create.newString;
 import static org.jruby.api.Error.*;
 import static org.jruby.runtime.marshal.MarshalCommon.TYPE_IVAR;
 import static org.jruby.runtime.marshal.MarshalCommon.TYPE_UCLASS;
@@ -532,7 +532,7 @@ public void writeEncoding(ThreadContext context, RubyOutputStream out, Encoding
             writeObjectData(context, out, context.tru);
         } else {
             writeAndRegisterSymbol(out, symbolTable.getEncodingSymbol());
-            RubyString encodingString = new RubyString(context.runtime, stringClass(context), encoding.getName());
+            RubyString encodingString = newString(context, encoding.getName());
             writeObjectData(context, out, encodingString);
         }
     }
diff --git a/core/src/main/java/org/jruby/util/RubyTimeParser.java b/core/src/main/java/org/jruby/util/RubyTimeParser.java
index ced67a4e37d..19d57e425cc 100644
--- a/core/src/main/java/org/jruby/util/RubyTimeParser.java
+++ b/core/src/main/java/org/jruby/util/RubyTimeParser.java
@@ -40,10 +40,10 @@ public IRubyObject parse(ThreadContext context, RubyTime self, RubyString str, I
         if (prec < 0) prec = Long.MAX_VALUE;
 
         if (!isEOS() && (isSpace() || Character.isWhitespace(bytes[end - 1]))) {
-            throw argumentError(context, str(context.runtime, "can't parse: ", str.inspect()));
+            throw argumentError(context, str(context.runtime, "can't parse: ", str.inspect(context)));
         }
         year = parseInt(context, true, Long.MAX_VALUE);
-        if (year.isNil()) throw argumentError(context, str(context.runtime, "can't parse: ", str.inspect()));
+        if (year.isNil()) throw argumentError(context, str(context.runtime, "can't parse: ", str.inspect(context)));
         if (ndigits < 4) {
             IRubyObject invalidYear = context.runtime.newString(new ByteList(bytes, ptr - ndigits - beg, ndigits, true));
             throw argumentError(context, str(context.runtime, "year must be 4 or more digits: ", invalidYear));