diff --git a/core/src/main/java/com/github/drinkjava2/frog/Application.java b/core/src/main/java/com/github/drinkjava2/frog/Application.java
index 8d96ff0..5eb97e0 100644
--- a/core/src/main/java/com/github/drinkjava2/frog/Application.java
+++ b/core/src/main/java/com/github/drinkjava2/frog/Application.java
@@ -21,12 +21,13 @@ public class Application {
 
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
+
 	public static JFrame mainFrame = new JFrame();
 	public static Env env = new Env();
 	public static BrainPicture brainPic = new BrainPicture(Env.ENV_WIDTH + 5, 0, Env.FROG_BRAIN_XSIZE,
diff --git a/eggs.ser b/eggs.ser
deleted file mode 100644
index cea85db..0000000
Binary files a/eggs.ser and /dev/null differ
diff --git a/history/001_first_version/eggs.ser b/history/001_first_version/eggs.ser
new file mode 100644
index 0000000..158e898
Binary files /dev/null and b/history/001_first_version/eggs.ser differ
diff --git a/history/001_first_version/src/main/java/com/github/drinkjava2/frog/env/Application.java b/history/001_first_version/src/main/java/com/github/drinkjava2/frog/env/Application.java
index 54aef5e..74d6a9d 100644
--- a/history/001_first_version/src/main/java/com/github/drinkjava2/frog/env/Application.java
+++ b/history/001_first_version/src/main/java/com/github/drinkjava2/frog/env/Application.java
@@ -11,11 +11,11 @@ public class Application {
 	public static final String CLASSPATH;
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
 	public static JFrame mainFrame = new JFrame();
 
diff --git a/history/002_first_eye/src/main/java/com/github/drinkjava2/frog/env/Application.java b/history/002_first_eye/src/main/java/com/github/drinkjava2/frog/env/Application.java
index 9e65b71..77cb0a6 100644
--- a/history/002_first_eye/src/main/java/com/github/drinkjava2/frog/env/Application.java
+++ b/history/002_first_eye/src/main/java/com/github/drinkjava2/frog/env/Application.java
@@ -20,11 +20,11 @@ public class Application {
 
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
 	public static JFrame mainFrame = new JFrame();
 	public static Env env = new Env();
diff --git a/history/003_trap/src/main/java/com/github/drinkjava2/frog/Application.java b/history/003_trap/src/main/java/com/github/drinkjava2/frog/Application.java
index 97afaea..7e1f34d 100644
--- a/history/003_trap/src/main/java/com/github/drinkjava2/frog/Application.java
+++ b/history/003_trap/src/main/java/com/github/drinkjava2/frog/Application.java
@@ -22,11 +22,11 @@ public class Application {
 
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
 	public static JFrame mainFrame = new JFrame();
 	public static Env env = new Env();
diff --git a/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/Application.java b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/Application.java
index 97afaea..7e1f34d 100644
--- a/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/Application.java
+++ b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/Application.java
@@ -22,11 +22,11 @@ public class Application {
 
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
 	public static JFrame mainFrame = new JFrame();
 	public static Env env = new Env();
diff --git a/history/005_letter_test/src/main/java/com/github/drinkjava2/frog/Application.java b/history/005_letter_test/src/main/java/com/github/drinkjava2/frog/Application.java
index 8d96ff0..b08eca9 100644
--- a/history/005_letter_test/src/main/java/com/github/drinkjava2/frog/Application.java
+++ b/history/005_letter_test/src/main/java/com/github/drinkjava2/frog/Application.java
@@ -21,11 +21,11 @@ public class Application {
 
 	static {
 		String classpath = new File("").getAbsolutePath();
-		int core = classpath.indexOf("\\frog\\");
-		if (core > 0)
-			CLASSPATH = classpath.substring(0, core) + "\\frog\\";
+		int i = classpath.indexOf("\\frog\\");
+		if (i > 0)
+			CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
 		else
-			CLASSPATH = classpath.substring(0, core) + "/frog/"; // UNIX
+			CLASSPATH = classpath + "/"; // UNIX
 	}
 	public static JFrame mainFrame = new JFrame();
 	public static Env env = new Env();