fixed checkstyle errors about utility classes constructors

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@811780 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/math/analysis/solvers/UnivariateRealSolverUtils.java

@@ -233,9 +233,15 @@ private static void setup(UnivariateRealFunction f) {
      * <p>We use here the Initialization On Demand Holder Idiom.</p>
      */
     private static class LazyHolder {
+
+        /** Private constructor. */
+        private LazyHolder() {
+        }
+
         /** Cached solver factory */
         private static final UnivariateRealSolverFactory FACTORY =
             UnivariateRealSolverFactory.newInstance();
+
     }
 
 }

src/main/java/org/apache/commons/math/complex/ComplexField.java

@@ -61,8 +61,14 @@ public Complex getZero() {
      * <p>We use here the Initialization On Demand Holder Idiom.</p>
      */
     private static class LazyHolder {
+
+        /** Private constructor. */
+        private LazyHolder() {
+        }
+
         /** Cached field instance. */
         private static final ComplexField INSTANCE = new ComplexField();
+
     }
 
     /** Handle deserialization of the singleton.

src/main/java/org/apache/commons/math/fraction/BigFractionField.java

@@ -61,8 +61,14 @@ public BigFraction getZero() {
      * <p>We use here the Initialization On Demand Holder Idiom.</p>
      */
     private static class LazyHolder {
+
+        /** Private constructor. */
+        private LazyHolder() {
+        }
+
         /** Cached field instance. */
         private static final BigFractionField INSTANCE = new BigFractionField();
+
     }
 
     /** Handle deserialization of the singleton.

src/main/java/org/apache/commons/math/fraction/FractionField.java

@@ -61,8 +61,14 @@ public Fraction getZero() {
      * <p>We use here the Initialization On Demand Holder Idiom.</p>
      */
     private static class LazyHolder {
+
+        /** Private constructor. */
+        private LazyHolder() {
+        }
+
         /** Cached field instance. */
         private static final FractionField INSTANCE = new FractionField();
+
     }
 
     /** Handle deserialization of the singleton.

src/main/java/org/apache/commons/math/stat/inference/OneWayAnovaImpl.java

@@ -199,7 +199,7 @@ private static class AnovaStats {
          * @param dfwg degrees of freedom in denominator (within groups)
          * @param F statistic
          */
-        AnovaStats(int dfbg, int dfwg, double F) {
+        public AnovaStats(int dfbg, int dfwg, double F) {
             this.dfbg = dfbg;
             this.dfwg = dfwg;
             this.F = F;

src/main/java/org/apache/commons/math/util/BigRealField.java

@@ -61,8 +61,14 @@ public BigReal getZero() {
      * <p>We use here the Initialization On Demand Holder Idiom.</p>
      */
     private static class LazyHolder {
+
+        /** Private constructor. */
+        private LazyHolder() {
+        }
+
         /** Cached field instance. */
         private static final BigRealField INSTANCE = new BigRealField();
+
     }
 
     /** Handle deserialization of the singleton.