diff --git a/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSession.java b/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSession.java
index 2163320da..3f1e269cf 100644
--- a/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSession.java
+++ b/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSession.java
@@ -40,6 +40,7 @@ public class AwsHttpSession implements HttpSession {
     private int maxInactiveInterval;
     private long lastAccessedTime;
     private boolean valid;
+    private boolean isNew = true;
 
     /**
      * @param id A unique session identifier
@@ -50,7 +51,7 @@ public AwsHttpSession(String id) {
         }
         this.id = id;
         attributes = new HashMap<>();
-        creationTime = Instant.now().getEpochSecond();
+        creationTime = Instant.now().toEpochMilli();
         maxInactiveInterval = SESSION_DURATION_SEC;
         lastAccessedTime = creationTime;
         valid = true;
@@ -118,18 +119,27 @@ public void invalidate() {
 
     @Override
     public boolean isNew() {
-        return lastAccessedTime == creationTime;
+       if (!valid) {
+           throw new IllegalStateException("Session is invalidated");
+       }
+       return isNew;
     }
 
     private void touch() {
-        lastAccessedTime = Instant.now().getEpochSecond();
+       lastAccessedTime = Instant.now().toEpochMilli();
+       isNew = false;
     }
 
     boolean isValid() {
-        if (lastAccessedTime - creationTime < maxInactiveInterval) {
-            return valid;
-        } else {
+        if (!valid) {
             return false;
         }
+
+        if (maxInactiveInterval <= 0) {
+            return true;
+        }
+
+        return Instant.now().toEpochMilli() - lastAccessedTime
+                < maxInactiveInterval * 1000L;
     }
 }
diff --git a/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSessionTest.java b/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSessionTest.java
index bcca83dda..c1f770a46 100644
--- a/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSessionTest.java
+++ b/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpSessionTest.java
@@ -28,8 +28,14 @@ void new_withValidId_setsIdCorrectly() {
 
     @Test
     void new_creationTimePopulatedCorrectly() {
+        long beforeCreation = Instant.now().toEpochMilli();
+
         AwsHttpSession session = new AwsHttpSession("id");
-        assertTrue(session.getCreationTime() > Instant.now().getEpochSecond() - 1);
+
+        long afterCreation = Instant.now().toEpochMilli();
+
+        assertTrue(session.getCreationTime() >= beforeCreation);
+        assertTrue(session.getCreationTime() <= afterCreation);
         assertEquals(AwsHttpSession.SESSION_DURATION_SEC, session.getMaxInactiveInterval());
         assertEquals(session.getLastAccessedTime(), session.getCreationTime());
     }
@@ -64,16 +70,30 @@ void attributes_dataStoredCorrectly() throws InterruptedException {
     }
 
     @Test
-    void validSession_expectCorrectValidationOrInvalidation() throws InterruptedException {
+    void validSession_expectCorrectValidationOrInvalidation() {
         AwsHttpSession sess = new AwsHttpSession("id");
+
         assertTrue(sess.isValid());
         assertTrue(sess.isNew());
 
-        Thread.sleep(1000);
         sess.setAttribute("test", "test");
+
         assertFalse(sess.isNew());
+
         sess.invalidate();
+
         assertFalse(sess.isValid());
-        assertNull(sess.getAttribute("test"));
+        assertThrows(IllegalStateException.class, sess::isNew);
+    }
+
+    @Test
+    void nonPositiveMaxInactiveIntervalDoesNotExpireSession() {
+        AwsHttpSession sess = new AwsHttpSession("id");
+
+        sess.setMaxInactiveInterval(0);
+        assertTrue(sess.isValid());
+
+        sess.setMaxInactiveInterval(-1);
+        assertTrue(sess.isValid());
     }
 }