fixed some Sonar violations

src/main/java/com/xeiam/xchart/AxisPair.java

@@ -130,15 +130,13 @@ public class AxisPair implements IChartPart {
 
   protected static int getTickSpace(int workingSpace) {
 
-    int tickSpace = (int) (workingSpace * 0.95);
-    return tickSpace;
+    return (int) (workingSpace * 0.95);
   }
 
   protected static int getMargin(int workingSpace, int tickSpace) {
 
     int marginSpace = workingSpace - tickSpace;
-    int margin = (int) (marginSpace / 2.0);
-    return margin;
+    return (int) (marginSpace / 2.0);
   }
 
   @Override

src/main/java/com/xeiam/xchart/BitmapEncoder.java

@@ -18,6 +18,7 @@ package com.xeiam.xchart;
 import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
 import java.io.FileOutputStream;
+import java.io.IOException;
 import java.io.OutputStream;
 
 import javax.imageio.ImageIO;
@@ -27,13 +28,21 @@ import javax.imageio.ImageIO;
  */
 public class BitmapEncoder {
 
+  /**
+   * Constructor - Private constructor to prevent instantiation
+   */
+  private BitmapEncoder() {
+
+  }
+
   /**
    * Saves a chart as a PNG file
    * 
    * @param chart
    * @param pFileName
+   * @throws IOException
    */
-  public static void savePNG(Chart chart, String pFileName) throws Exception {
+  public static void savePNG(Chart chart, String pFileName) throws IOException {
 
     BufferedImage lBufferedImage = new BufferedImage(chart.width, chart.height, BufferedImage.TYPE_INT_RGB);
     Graphics2D lGraphics2D = lBufferedImage.createGraphics();

src/main/java/com/xeiam/xchart/ServletEncoder.java

@@ -17,6 +17,7 @@ package com.xeiam.xchart;
 
 import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
+import java.io.IOException;
 
 import javax.imageio.ImageIO;
 import javax.servlet.ServletOutputStream;
@@ -26,13 +27,21 @@ import javax.servlet.ServletOutputStream;
  */
 public class ServletEncoder {
 
+  /**
+   * Constructor - Private constructor to prevent instantiation
+   */
+  private ServletEncoder() {
+
+  }
+
   /**
    * Streams a chart as a PNG file
    * 
    * @param out
    * @param chart
+   * @throws IOException
    */
-  public static void streamPNG(ServletOutputStream out, Chart chart) throws Exception {
+  public static void streamPNG(ServletOutputStream out, Chart chart) throws IOException {
 
     BufferedImage lBufferedImage = new BufferedImage(chart.width, chart.height, BufferedImage.TYPE_INT_RGB);
     Graphics2D lGraphics2D = lBufferedImage.createGraphics();