diff --git a/src/de/schildbach/pte/AbstractEfaProvider.java b/src/de/schildbach/pte/AbstractEfaProvider.java
index e233df52..9d3e7c00 100644
--- a/src/de/schildbach/pte/AbstractEfaProvider.java
+++ b/src/de/schildbach/pte/AbstractEfaProvider.java
@@ -1267,7 +1267,7 @@ public abstract class AbstractEfaProvider implements NetworkProvider
 
 	public int[] lineColors(final String line)
 	{
-		if (line.isEmpty())
+		if (line.length() == 0)
 			return null;
 		return LINES.get(line.charAt(0));
 	}
diff --git a/src/de/schildbach/pte/AbstractHafasProvider.java b/src/de/schildbach/pte/AbstractHafasProvider.java
index 96f520c6..f7392b62 100644
--- a/src/de/schildbach/pte/AbstractHafasProvider.java
+++ b/src/de/schildbach/pte/AbstractHafasProvider.java
@@ -921,7 +921,7 @@ public abstract class AbstractHafasProvider implements NetworkProvider
 
 	public final int[] lineColors(final String line)
 	{
-		if (line.isEmpty())
+		if (line.length() == 0)
 			return null;
 		return LINES.get(line.charAt(0));
 	}
diff --git a/src/de/schildbach/pte/BvgProvider.java b/src/de/schildbach/pte/BvgProvider.java
index b696df2c..7bdeb82f 100644
--- a/src/de/schildbach/pte/BvgProvider.java
+++ b/src/de/schildbach/pte/BvgProvider.java
@@ -746,7 +746,7 @@ public final class BvgProvider implements NetworkProvider
 
 	public int[] lineColors(final String line)
 	{
-		if (line.isEmpty())
+		if (line.length() == 0)
 			return null;
 		return LINES.get(line);
 	}