diff --git a/core/src/main/java/tech/tablesaw/io/DataFrameReader.java b/core/src/main/java/tech/tablesaw/io/DataFrameReader.java
index ce06dd41a..7e1ae8785 100644
--- a/core/src/main/java/tech/tablesaw/io/DataFrameReader.java
+++ b/core/src/main/java/tech/tablesaw/io/DataFrameReader.java
@@ -56,14 +56,13 @@ public Table url(String url) {
    * mime-type Use {@link #usingOptions(ReadOptions) usingOptions} to use non-default options
    */
   public Table url(URL url) {
-    URLConnection connection = null;
     try {
-      connection = url.openConnection();
+      URLConnection connection = url.openConnection();
+      String contentType = connection.getContentType();
+      return url(url, getCharset(contentType), getMimeType(contentType));
     } catch (IOException e) {
-      e.printStackTrace();
+      throw new RuntimeIOException(e);
     }
-    String contentType = connection.getContentType();
-    return url(url, getCharset(contentType), getMimeType(contentType));
   }
 
   private Table url(URL url, Charset charset, String mimeType) {
@@ -87,11 +86,17 @@ private Table readUrl(URL url, Charset charset, DataReader<?> reader) {
   }
 
   private String getMimeType(String contentType) {
+    if (contentType == null) {
+      return null;
+    }
     String[] pair = contentType.split(";");
     return pair[0].trim();
   }
 
   private Charset getCharset(String contentType) {
+    if (contentType == null) {
+      return Charset.defaultCharset();
+    }
     String[] pair = contentType.split(";");
     return pair.length == 1
         ? Charset.defaultCharset()
diff --git a/core/src/test/java/tech/tablesaw/io/DataFrameReaderTest.java b/core/src/test/java/tech/tablesaw/io/DataFrameReaderTest.java
index 374b11af2..313be26f8 100644
--- a/core/src/test/java/tech/tablesaw/io/DataFrameReaderTest.java
+++ b/core/src/test/java/tech/tablesaw/io/DataFrameReaderTest.java
@@ -6,6 +6,7 @@
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
 import java.io.IOException;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.nio.file.FileSystem;
 import java.nio.file.Files;
@@ -81,4 +82,16 @@ public void readUrlUnknownMimeTypeNoExtension() throws Exception {
             .getMessage()
             .contains("No reader registered for mime-type application/octet-stream"));
   }
+  
+  @Test
+  void readInvalidURL() throws MalformedURLException {
+      URL url = new URL("ftp://not-a-host/data.csv");
+      assertThrows(RuntimeIOException.class, () -> Table.read().url(url));
+  }
+
+  @Test
+  void readInvalidURLNoExtension() throws MalformedURLException {
+      URL url = new URL("ftp://not-a-host/data/csv");
+      assertThrows(IllegalArgumentException.class, () -> Table.read().url(url));
+  }
 }