2 files changed, 33 insertions, 28 deletions

diff --git a/src/main/java/au/id/zancanaro/javacheck/junit/Properties.java b/src/main/java/au/id/zancanaro/javacheck/junit/Properties.java
index 6ff0538..1e3f502 100644
--- a/src/main/java/au/id/zancanaro/javacheck/junit/Properties.java
+++ b/src/main/java/au/id/zancanaro/javacheck/junit/Properties.java
@@ -16,6 +16,7 @@ import org.junit.runners.model.TestClass;
 import java.lang.reflect.*;
 import java.util.*;
 
+@SuppressWarnings("WeakerAccess")
 public class Properties extends BlockJUnit4ClassRunner {
     private final Map<Type, Generator<?>> generators = new HashMap<>();
 
@@ -35,32 +36,36 @@ public class Properties extends BlockJUnit4ClassRunner {
         Field[] fields = getTestClass().getJavaClass().getDeclaredFields();
 
         for (Field field : fields) {
-            if (!field.isAnnotationPresent(DataSource.class)) {
-                continue;
-            }
-            Type type = field.getGenericType();
-            if (!(type instanceof ParameterizedType)) {
-                continue;
-            }
-            ParameterizedType parameterizedType = (ParameterizedType) type;
-            if (!(parameterizedType.getRawType() instanceof Class)) {
-                continue;
-            }
-            Class<?> c = (Class) parameterizedType.getRawType();
-            if (c != Generator.class) {
-                continue;
-            }
-            boolean error = false;
-            if (!Modifier.isStatic(field.getModifiers())) {
-                errors.add(new Error("Generator field " + field.getName() + " must be static"));
-                error = true;
-            }
-            if (!Modifier.isPublic(field.getModifiers())) {
-                errors.add(new Error("Generator field " + field.getName() + " must be public"));
-                error = true;
-            }
-            if (!error) {
-                result.add(parameterizedType.getActualTypeArguments()[0]);
+            if (field.isAnnotationPresent(DataSource.class)) {
+                boolean error = false;
+                if (!Modifier.isStatic(field.getModifiers())) {
+                    errors.add(new Error("@DataSource field " + field.getName() + " must be static"));
+                    error = true;
+                }
+                if (!Modifier.isPublic(field.getModifiers())) {
+                    errors.add(new Error("@DataSource field " + field.getName() + " must be public"));
+                    error = true;
+                }
+
+                Type type = field.getGenericType();
+                ParameterizedType parameterizedType;;
+                if (type instanceof ParameterizedType) {
+                    parameterizedType = (ParameterizedType) type;
+                    if (parameterizedType.getRawType() instanceof Class) {
+                        Class<?> c = (Class) parameterizedType.getRawType();
+                        if (c == Generator.class) {
+                            if (!error) {
+                                result.add(parameterizedType.getActualTypeArguments()[0]);
+                            }
+                        } else {
+                            errors.add(new Error("@DataSource fields must be of type Generator<T>"));
+                        }
+                    } else {
+                        errors.add(new Error("@DataSource fields must be of type Generator<T>"));
+                    }
+                } else {
+                    errors.add(new Error("@DataSource fields must be of type Generator<T>"));
+                }
             }
         }
         return result;
diff --git a/src/main/java/au/id/zancanaro/javacheck/junit/PropertyError.java b/src/main/java/au/id/zancanaro/javacheck/junit/PropertyError.java
index 2cd1325..44c071b 100644
--- a/src/main/java/au/id/zancanaro/javacheck/junit/PropertyError.java
+++ b/src/main/java/au/id/zancanaro/javacheck/junit/PropertyError.java
@@ -5,6 +5,7 @@ import au.id.zancanaro.javacheck.ShrinkResult;
 import java.util.Arrays;
 import java.util.Iterator;
 
+@SuppressWarnings("WeakerAccess")
 public class PropertyError extends AssertionError {
     public PropertyError(String methodName, long seed, ShrinkResult shrunk) {
         super(shrunk.thrown.getMessage() == null ?
@@ -18,8 +19,7 @@ public class PropertyError extends AssertionError {
         initCause(shrunk.thrown);
     }
 
-
-    public static String joinArgs(Object... params) {
+    private static String joinArgs(Object... params) {
         StringBuilder sb = new StringBuilder();
         Iterator<Object> iterator = Arrays.asList(params).iterator();
         while (iterator.hasNext()) {