diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFCategoryAxis.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFCategoryAxis.java
index acc97f6245..115389b5fc 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFCategoryAxis.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFCategoryAxis.java
@@ -23,6 +23,7 @@ import org.apache.poi.ss.usermodel.charts.AxisPosition;
 import org.apache.poi.ss.usermodel.charts.AxisTickMark;
 import org.apache.poi.ss.usermodel.charts.ChartAxis;
 import org.apache.poi.util.Beta;
+import org.apache.poi.util.Internal;
 import org.apache.poi.xssf.usermodel.XSSFChart;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTAxPos;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTBoolean;
@@ -55,18 +56,23 @@ public class XSSFCategoryAxis extends XSSFChartAxis {
 		this.ctCatAx = ctCatAx;
 	}
 
+	@Override
 	public long getId() {
 		return ctCatAx.getAxId().getVal();
 	}
 
+	@Override
+	@Internal
 	public CTShapeProperties getLine() {
 	    return ctCatAx.getSpPr();
 	}
 	
+	@Override
 	protected CTAxPos getCTAxPos() {
 		return ctCatAx.getAxPos();
 	}
 
+	@Override
 	protected CTNumFmt getCTNumFmt() {
 		if (ctCatAx.isSetNumFmt()) {
 			return ctCatAx.getNumFmt();
@@ -74,10 +80,12 @@ public class XSSFCategoryAxis extends XSSFChartAxis {
 		return ctCatAx.addNewNumFmt();
 	}
 
+	@Override
 	protected CTScaling getCTScaling() {
 		return ctCatAx.getScaling();
 	}
 
+	@Override
 	protected CTCrosses getCTCrosses() {
 		return ctCatAx.getCrosses();
 	}
@@ -97,10 +105,13 @@ public class XSSFCategoryAxis extends XSSFChartAxis {
 		return ctCatAx.getMinorTickMark();
 	}
 
+	@Override
+	@Internal
 	public CTChartLines getMajorGridLines() {
 	    return ctCatAx.getMajorGridlines();
 	}
 	
+	@Override
 	public void crossAxis(ChartAxis axis) {
 		ctCatAx.getCrossAx().setVal(axis.getId());
 	}
@@ -125,6 +136,7 @@ public class XSSFCategoryAxis extends XSSFChartAxis {
 		setMinorTickMark(AxisTickMark.NONE);
 	}
 
+	@Override
     public boolean hasNumberFormat() {
         return ctCatAx.isSetNumFmt();
     }
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFChartAxis.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFChartAxis.java
index 41e0f148eb..10d6929408 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFChartAxis.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFChartAxis.java
@@ -23,6 +23,7 @@ import org.apache.poi.ss.usermodel.charts.AxisPosition;
 import org.apache.poi.ss.usermodel.charts.AxisTickMark;
 import org.apache.poi.ss.usermodel.charts.ChartAxis;
 import org.apache.poi.util.Beta;
+import org.apache.poi.util.Internal;
 import org.apache.poi.xssf.usermodel.XSSFChart;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTAxPos;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTBoolean;
@@ -56,27 +57,33 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		this.chart = chart;
 	}
 
+	@Override
 	public AxisPosition getPosition() {
 		return toAxisPosition(getCTAxPos());
 	}
 
+	@Override
 	public void setPosition(AxisPosition position) {
 		getCTAxPos().setVal(fromAxisPosition(position));
 	}
 
+	@Override
 	public void setNumberFormat(String format) {
 		getCTNumFmt().setFormatCode(format);
 		getCTNumFmt().setSourceLinked(true);
 	}
 
+	@Override
 	public String getNumberFormat() {
 		return getCTNumFmt().getFormatCode();
 	}
 
+	@Override
 	public boolean isSetLogBase() {
 		return getCTScaling().isSetLogBase();
 	}
 
+	@Override
 	public void setLogBase(double logBase) {
 		if (logBase < MIN_LOG_BASE ||
 			MAX_LOG_BASE < logBase) {
@@ -90,6 +97,7 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public double getLogBase() {
 		CTLogBase logBase = getCTScaling().getLogBase();
 		if (logBase != null) {
@@ -98,10 +106,12 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		return 0.0;
 	}
 
+	@Override
 	public boolean isSetMinimum() {
 		return getCTScaling().isSetMin();
 	}
 
+	@Override
 	public void setMinimum(double min) {
 		CTScaling scaling = getCTScaling();
 		if (scaling.isSetMin()) {
@@ -111,6 +121,7 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public double getMinimum() {
 		CTScaling scaling = getCTScaling();
 		if (scaling.isSetMin()) {
@@ -120,10 +131,12 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public boolean isSetMaximum() {
 		return getCTScaling().isSetMax();
 	}
 
+	@Override
 	public void setMaximum(double max) {
 		CTScaling scaling = getCTScaling();
 		if (scaling.isSetMax()) {
@@ -133,6 +146,7 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public double getMaximum() {
 		CTScaling scaling = getCTScaling();
 		if (scaling.isSetMax()) {
@@ -142,10 +156,12 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public AxisOrientation getOrientation() {
 		return toAxisOrientation(getCTScaling().getOrientation());
 	}
 
+	@Override
 	public void setOrientation(AxisOrientation orientation) {
 		CTScaling scaling = getCTScaling();
 		STOrientation.Enum stOrientation = fromAxisOrientation(orientation);
@@ -156,34 +172,42 @@ public abstract class XSSFChartAxis implements ChartAxis {
 		}
 	}
 
+	@Override
 	public AxisCrosses getCrosses() {
 		return toAxisCrosses(getCTCrosses());
 	}
 
+	@Override
 	public void setCrosses(AxisCrosses crosses) {
 		getCTCrosses().setVal(fromAxisCrosses(crosses));
 	}
 
+	@Override
 	public boolean isVisible() {
 		return !getDelete().getVal();
 	}
 
+	@Override
 	public void setVisible(boolean value) {
 		getDelete().setVal(!value);
 	}
 
+	@Override
 	public AxisTickMark getMajorTickMark() {
 		return toAxisTickMark(getMajorCTTickMark());
 	}
 
+	@Override
 	public void setMajorTickMark(AxisTickMark tickMark) {
 		getMajorCTTickMark().setVal(fromAxisTickMark(tickMark));
 	}
 
+	@Override
 	public AxisTickMark getMinorTickMark() {
 		return toAxisTickMark(getMinorCTTickMark());
 	}
 
+	@Override
 	public void setMinorTickMark(AxisTickMark tickMark) {
 		getMinorCTTickMark().setVal(fromAxisTickMark(tickMark));
 	}
@@ -195,8 +219,8 @@ public abstract class XSSFChartAxis implements ChartAxis {
 	protected abstract CTBoolean getDelete();
 	protected abstract CTTickMark getMajorCTTickMark();
 	protected abstract CTTickMark getMinorCTTickMark();
-	public abstract CTChartLines getMajorGridLines();
-	public abstract CTShapeProperties getLine();
+	@Internal public abstract CTChartLines getMajorGridLines();
+	@Internal public abstract CTShapeProperties getLine();
 	
 	private static STOrientation.Enum fromAxisOrientation(AxisOrientation orientation) {
 		switch (orientation) {
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFDateAxis.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFDateAxis.java
index 186d1ffa3f..658c4e3525 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFDateAxis.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFDateAxis.java
@@ -23,10 +23,10 @@ import org.apache.poi.ss.usermodel.charts.AxisPosition;
 import org.apache.poi.ss.usermodel.charts.AxisTickMark;
 import org.apache.poi.ss.usermodel.charts.ChartAxis;
 import org.apache.poi.util.Beta;
+import org.apache.poi.util.Internal;
 import org.apache.poi.xssf.usermodel.XSSFChart;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTAxPos;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTBoolean;
-import org.openxmlformats.schemas.drawingml.x2006.chart.CTCatAx;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTChartLines;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTCrosses;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTDateAx;
@@ -63,18 +63,23 @@ public class XSSFDateAxis extends XSSFChartAxis {
 		this.ctDateAx = ctDateAx;
 	}
 
+	@Override
 	public long getId() {
 		return ctDateAx.getAxId().getVal();
 	}
 
+	@Override
+	@Internal
     public CTShapeProperties getLine() {
         return ctDateAx.getSpPr();
     }
 
+	@Override
 	protected CTAxPos getCTAxPos() {
 		return ctDateAx.getAxPos();
 	}
 
+	@Override
 	protected CTNumFmt getCTNumFmt() {
 		if (ctDateAx.isSetNumFmt()) {
 			return ctDateAx.getNumFmt();
@@ -82,10 +87,12 @@ public class XSSFDateAxis extends XSSFChartAxis {
 		return ctDateAx.addNewNumFmt();
 	}
 
+	@Override
 	protected CTScaling getCTScaling() {
 		return ctDateAx.getScaling();
 	}
 
+	@Override
 	protected CTCrosses getCTCrosses() {
 		return ctDateAx.getCrosses();
 	}
@@ -105,10 +112,13 @@ public class XSSFDateAxis extends XSSFChartAxis {
 		return ctDateAx.getMinorTickMark();
 	}
 
+	@Override
+	@Internal
 	public CTChartLines getMajorGridLines() {
 	    return ctDateAx.getMajorGridlines();
 	}
 	
+	@Override
 	public void crossAxis(ChartAxis axis) {
 		ctDateAx.getCrossAx().setVal(axis.getId());
 	}
@@ -133,6 +143,7 @@ public class XSSFDateAxis extends XSSFChartAxis {
 		setMinorTickMark(AxisTickMark.NONE);
 	}
 
+	@Override
     public boolean hasNumberFormat() {
         return ctDateAx.isSetNumFmt();
     }
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFValueAxis.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFValueAxis.java
index 0e31f03eeb..3dea67ddb4 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFValueAxis.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/charts/XSSFValueAxis.java
@@ -25,6 +25,7 @@ import org.apache.poi.ss.usermodel.charts.AxisTickMark;
 import org.apache.poi.ss.usermodel.charts.ChartAxis;
 import org.apache.poi.ss.usermodel.charts.ValueAxis;
 import org.apache.poi.util.Beta;
+import org.apache.poi.util.Internal;
 import org.apache.poi.xssf.usermodel.XSSFChart;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTAxPos;
 import org.openxmlformats.schemas.drawingml.x2006.chart.CTBoolean;
@@ -58,18 +59,23 @@ public class XSSFValueAxis extends XSSFChartAxis implements ValueAxis {
 		this.ctValAx = ctValAx;
 	}
 
+	@Override
 	public long getId() {
 		return ctValAx.getAxId().getVal();
 	}
 
+	@Override
+	@Internal
     public CTShapeProperties getLine() {
         return ctValAx.getSpPr();
     }
 
+	@Override
 	public void setCrossBetween(AxisCrossBetween crossBetween) {
 		ctValAx.getCrossBetween().setVal(fromCrossBetween(crossBetween));
 	}
 
+	@Override
 	public AxisCrossBetween getCrossBetween() {
 		return toCrossBetween(ctValAx.getCrossBetween().getVal());
 	}
@@ -112,10 +118,13 @@ public class XSSFValueAxis extends XSSFChartAxis implements ValueAxis {
 		return ctValAx.getMinorTickMark();
 	}
 
+	@Override
+	@Internal
     public CTChartLines getMajorGridLines() {
         return ctValAx.getMajorGridlines();
     }
 
+    @Override
 	public void crossAxis(ChartAxis axis) {
 		ctValAx.getCrossAx().setVal(axis.getId());
 	}
@@ -160,6 +169,7 @@ public class XSSFValueAxis extends XSSFChartAxis implements ValueAxis {
 		}
 	}
 
+	@Override
     public boolean hasNumberFormat() {
         return ctValAx.isSetNumFmt();
     }