diff --git a/core/src/processing/data/FloatList.java b/core/src/processing/data/FloatList.java
index 230b5fc36..9921cb326 100644
--- a/core/src/processing/data/FloatList.java
+++ b/core/src/processing/data/FloatList.java
@@ -749,6 +749,20 @@ public class FloatList implements Iterable<Float> {
   }
 
 
+  public String join(String separator) {
+    if (count == 0) {
+      return "";
+    }
+    StringBuilder sb = new StringBuilder();
+    sb.append(data[0]);
+    for (int i = 1; i < count; i++) {
+      sb.append(separator);
+      sb.append(data[i]);
+    }
+    return sb.toString();
+  }
+
+
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder();
diff --git a/core/src/processing/data/IntList.java b/core/src/processing/data/IntList.java
index 10ed4ac34..1b8860fcc 100644
--- a/core/src/processing/data/IntList.java
+++ b/core/src/processing/data/IntList.java
@@ -757,6 +757,20 @@ public class IntList implements Iterable<Integer> {
   }
 
 
+  public String join(String separator) {
+    if (count == 0) {
+      return "";
+    }
+    StringBuilder sb = new StringBuilder();
+    sb.append(data[0]);
+    for (int i = 1; i < count; i++) {
+      sb.append(separator);
+      sb.append(data[i]);
+    }
+    return sb.toString();
+  }
+
+
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder();
diff --git a/core/src/processing/data/StringList.java b/core/src/processing/data/StringList.java
index ce13fca94..309d45181 100644
--- a/core/src/processing/data/StringList.java
+++ b/core/src/processing/data/StringList.java
@@ -688,6 +688,20 @@ public class StringList implements Iterable<String> {
 //  }
 
 
+  public String join(String separator) {
+    if (count == 0) {
+      return "";
+    }
+    StringBuilder sb = new StringBuilder();
+    sb.append(data[0]);
+    for (int i = 1; i < count; i++) {
+      sb.append(separator);
+      sb.append(data[i]);
+    }
+    return sb.toString();
+  }
+
+
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder();
diff --git a/core/todo.txt b/core/todo.txt
index a5ab4c444..82e694752 100644
--- a/core/todo.txt
+++ b/core/todo.txt
@@ -28,6 +28,7 @@ X   perhaps it's a getGraphics() issue?
 X when using increment() on IntList, make sure the index exists
 X   automatically resize the list if necessary
 X   (this is more in keeping with increment() in the Dict classes)
+X add join() method to Int/Float/StringList
 
 cleaning
 X load/save methods.. is it save("blah.svg") or saveSVG("blah.svg")
@@ -41,6 +42,8 @@ _   https://github.com/processing/processing/issues/2012
 _ add option to have full screen span across screens
 _   display=all in cmd line
 _   sketchDisplay() -> 0 for all, or 1, 2, 3...
+_ add optional/default values for get methods in JSON
+_ add isNull() method back to JSONObject/Array
 
 _ test PGraphicsRetina2D w/ 7u40 
 _ make sure that 7u40 doesn't reintroduce starvation issue on retina Macs