diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index a78f1d54f..a7b95a65e 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -306,6 +306,10 @@ axes:
         display_name: ruby-2.7
         variables:
            RVM_RUBY: ruby-2.7
+      - id: jruby-10.1
+        display_name: jruby-10.1
+        variables:
+           RVM_RUBY: jruby-10.1
       - id: jruby-10.0
         display_name: jruby-10.0
         variables:
@@ -410,7 +414,7 @@ buildvariants:
       - name: "test"
 
   - matrix_name: "jruby"
-    matrix_spec: { ruby: ["jruby-10.0", "jruby-9.4", "jruby-9.3"], all-os: ubuntu2404 }
+    matrix_spec: { ruby: ["jruby-10.1", "jruby-10.0", "jruby-9.4", "jruby-9.3"], all-os: ubuntu2404 }
     display_name: "${ruby}, ${all-os}"
     tasks:
       - name: "test"
diff --git a/.evergreen/update-evergreen-configs b/.evergreen/update-evergreen-configs
index fdaeaa0d1..ae6014881 100755
--- a/.evergreen/update-evergreen-configs
+++ b/.evergreen/update-evergreen-configs
@@ -106,7 +106,7 @@ module ConfigProcessor
 
   # all supported JRuby versions provided by 10gen/mongo-ruby-toolchain
   def jrubies
-    @jrubies ||= %w[ jruby-10.0 jruby-9.4 jruby-9.3 ]
+    @jrubies ||= %w[ jruby-10.1 jruby-10.0 jruby-9.4 jruby-9.3 ]
   end
 
   # all supported MRI ruby versions
diff --git a/src/main/org/bson_ruby/ByteBuf.java b/src/main/org/bson_ruby/ByteBuf.java
index 9cdc31e64..a26a65fb1 100644
--- a/src/main/org/bson_ruby/ByteBuf.java
+++ b/src/main/org/bson_ruby/ByteBuf.java
@@ -153,7 +153,7 @@ public IRubyObject initialize(final RubyString value) {
    */
   @JRubyMethod(name = "length")
   public RubyFixnum getLength(ThreadContext context) {
-    return new RubyFixnum(context.runtime, getLengthInternal());
+    return RubyFixnum.newFixnum(context.runtime, getLengthInternal());
   }
 
   private int getLengthInternal() {
@@ -173,7 +173,7 @@ private int getLengthInternal() {
    */
   @JRubyMethod(name = "read_position")
   public RubyFixnum getReadPosition(ThreadContext context) {
-    return new RubyFixnum(context.runtime, this.readPosition);
+    return RubyFixnum.newFixnum(context.runtime, this.readPosition);
   }
 
   /**
@@ -185,7 +185,7 @@ public RubyFixnum getReadPosition(ThreadContext context) {
    */
   @JRubyMethod(name = "write_position")
   public RubyFixnum getWritePosition(ThreadContext context) {
-    return new RubyFixnum(context.runtime, this.writePosition);
+    return RubyFixnum.newFixnum(context.runtime, this.writePosition);
   }
 
  /**
@@ -287,7 +287,7 @@ public RubyString getCString(ThreadContext context) {
    */
   @JRubyMethod(name = "get_decimal128_bytes")
   public RubyString getDecimal128Bytes() {
-    return getBytes(new RubyFixnum(getRuntime(), 16));
+    return getBytes(RubyFixnum.newFixnum(getRuntime(), 16));
   }
 
   /**
@@ -315,7 +315,7 @@ public RubyFloat getDouble() {
   @JRubyMethod(name = "get_int32")
   public RubyFixnum getInt32() {
     ensureBsonRead();
-    RubyFixnum int32 = new RubyFixnum(getRuntime(), this.buffer.getInt());
+    RubyFixnum int32 = RubyFixnum.newFixnum(getRuntime(), this.buffer.getInt());
     this.readPosition += 4;
     return int32;
   }
@@ -335,7 +335,7 @@ public RubyFixnum getUInt32() {
       temp += UINT32_MAX + 1;
     }
 
-    RubyFixnum int32 = new RubyFixnum(getRuntime(), temp);
+    RubyFixnum int32 = RubyFixnum.newFixnum(getRuntime(), temp);
     this.readPosition += 4;
     return int32;
   }
@@ -380,7 +380,7 @@ public RubyString getString(ThreadContext context) {
   @JRubyMethod(name = "get_int64")
   public RubyFixnum getInt64() {
     ensureBsonRead();
-    RubyFixnum int64 = new RubyFixnum(getRuntime(), this.buffer.getLong());
+    RubyFixnum int64 = RubyFixnum.newFixnum(getRuntime(), this.buffer.getLong());
     this.readPosition += 8;
     return int64;
   }