Set initial array list size

src/main/java/com/networknt/schema/AdditionalPropertiesValidator.java

@@ -71,7 +71,7 @@ public AdditionalPropertiesValidator(SchemaLocation schemaLocation, JsonNodePath
 
         JsonNode patternPropertiesNode = parentSchema.getSchemaNode().get(PatternPropertiesValidator.PROPERTY);
         if (patternPropertiesNode != null) {
-            this.patternProperties = new ArrayList<>();
+            this.patternProperties = new ArrayList<>(patternPropertiesNode.size());
             for (Iterator<String> it = patternPropertiesNode.fieldNames(); it.hasNext(); ) {
                 patternProperties.add(RegularExpression.compile(it.next(), validationContext));
             }

src/main/java/com/networknt/schema/AllOfValidator.java

@@ -31,7 +31,7 @@
 public class AllOfValidator extends BaseJsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(AllOfValidator.class);
 
-    private final List<JsonSchema> schemas = new ArrayList<>();
+    private final List<JsonSchema> schemas;
 
     public AllOfValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath, JsonNode schemaNode, JsonSchema parentSchema, ValidationContext validationContext) {
         super(schemaLocation, evaluationPath, schemaNode, parentSchema, ValidatorTypeCode.ALL_OF, validationContext);
@@ -44,6 +44,7 @@ public AllOfValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath
                     .build());
         }
         int size = schemaNode.size();
+        this.schemas = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
             this.schemas.add(validationContext.newSchema(schemaLocation.append(i), evaluationPath.append(i),
                     schemaNode.get(i), parentSchema));

src/main/java/com/networknt/schema/AnyOfValidator.java

@@ -31,7 +31,7 @@ public class AnyOfValidator extends BaseJsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(AnyOfValidator.class);
     private static final String DISCRIMINATOR_REMARK = "and the discriminator-selected candidate schema didn't pass validation";
 
-    private final List<JsonSchema> schemas = new ArrayList<>();
+    private final List<JsonSchema> schemas;
 
     private Boolean canShortCircuit = null;
 
@@ -46,6 +46,7 @@ public AnyOfValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath
                     .build());
         }
         int size = schemaNode.size();
+        this.schemas = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
             this.schemas.add(validationContext.newSchema(schemaLocation.append(i), evaluationPath.append(i),
                     schemaNode.get(i), parentSchema));

src/main/java/com/networknt/schema/ItemsValidator.java

@@ -50,15 +50,16 @@ public ItemsValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath
 
         Boolean additionalItems = null;
 
-        this.tupleSchema = new ArrayList<>();
         JsonSchema foundSchema = null;
         JsonSchema foundAdditionalSchema = null;
         JsonNode additionalItemsSchemaNode = null;
 
         if (schemaNode.isObject() || schemaNode.isBoolean()) {
             foundSchema = validationContext.newSchema(schemaLocation, evaluationPath, schemaNode, parentSchema);
+            this.tupleSchema = Collections.emptyList();
         } else {
             int i = 0;
+            this.tupleSchema = new ArrayList<>(schemaNode.size());
             for (JsonNode s : schemaNode) {
                 this.tupleSchema.add(validationContext.newSchema(schemaLocation.append(i), evaluationPath.append(i),
                         s, parentSchema));

src/main/java/com/networknt/schema/JsonSchema.java

@@ -420,8 +420,9 @@ private JsonNode handleNullNode(String ref, JsonSchema schema) {
      * Please note that the key in {@link #validators} map is the evaluation path.
      */
     private List<JsonValidator> read(JsonNode schemaNode) {
-        List<JsonValidator> validators = new ArrayList<>();
+        List<JsonValidator> validators;
         if (schemaNode.isBoolean()) {
+            validators = new ArrayList<>(1);
             if (schemaNode.booleanValue()) {
                 JsonNodePath path = getEvaluationPath().append("true");
                 JsonValidator validator = this.validationContext.newValidator(getSchemaLocation().append("true"), path,
@@ -437,6 +438,7 @@ private List<JsonValidator> read(JsonNode schemaNode) {
             JsonValidator refValidator = null;
 
             Iterator<Entry<String, JsonNode>> iterator = schemaNode.fields();
+            validators = new ArrayList<>(schemaNode.size());
             while (iterator.hasNext()) {
                 Entry<String, JsonNode> entry = iterator.next();
                 String pname = entry.getKey();

src/main/java/com/networknt/schema/NotAllowedValidator.java

@@ -28,15 +28,18 @@
 public class NotAllowedValidator extends BaseJsonValidator implements JsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(NotAllowedValidator.class);
 
-    private final List<String> fieldNames = new ArrayList<>();
+    private final List<String> fieldNames;
 
     public NotAllowedValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath, JsonNode schemaNode, JsonSchema parentSchema, ValidationContext validationContext) {
         super(schemaLocation, evaluationPath, schemaNode, parentSchema, ValidatorTypeCode.NOT_ALLOWED, validationContext);
         if (schemaNode.isArray()) {
             int size = schemaNode.size();
+            this.fieldNames = new ArrayList<>(size);
             for (int i = 0; i < size; i++) {
                 fieldNames.add(schemaNode.get(i).asText());
             }
+        } else {
+            this.fieldNames = Collections.emptyList();
         }
     }
 

src/main/java/com/networknt/schema/OneOfValidator.java

@@ -30,7 +30,7 @@
 public class OneOfValidator extends BaseJsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(OneOfValidator.class);
 
-    private final List<JsonSchema> schemas = new ArrayList<>();
+    private final List<JsonSchema> schemas;
 
     private Boolean canShortCircuit = null;
 
@@ -45,6 +45,7 @@ public OneOfValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath
                     .build());
         }
         int size = schemaNode.size();
+        this.schemas = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
             JsonNode childNode = schemaNode.get(i);
             this.schemas.add(validationContext.newSchema( schemaLocation.append(i), evaluationPath.append(i), childNode, parentSchema));

src/main/java/com/networknt/schema/PrefixItemsValidator.java

@@ -44,10 +44,9 @@ public class PrefixItemsValidator extends BaseJsonValidator {
     public PrefixItemsValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath, JsonNode schemaNode, JsonSchema parentSchema, ValidationContext validationContext) {
         super(schemaLocation, evaluationPath, schemaNode, parentSchema, ValidatorTypeCode.PREFIX_ITEMS, validationContext);
 
-        this.tupleSchema = new ArrayList<>();
-
         if (schemaNode instanceof ArrayNode && 0 < schemaNode.size()) {
             int i = 0;
+            this.tupleSchema = new ArrayList<>(schemaNode.size());
             for (JsonNode s : schemaNode) {
                 this.tupleSchema.add(validationContext.newSchema(schemaLocation.append(i), evaluationPath.append(i), s,
                         parentSchema));

src/main/java/com/networknt/schema/RequiredValidator.java

@@ -28,14 +28,17 @@
 public class RequiredValidator extends BaseJsonValidator implements JsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(RequiredValidator.class);
 
-    private final List<String> fieldNames = new ArrayList<>();
+    private final List<String> fieldNames;
 
     public RequiredValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath, JsonNode schemaNode, JsonSchema parentSchema, ValidationContext validationContext) {
         super(schemaLocation, evaluationPath, schemaNode, parentSchema, ValidatorTypeCode.REQUIRED, validationContext);
         if (schemaNode.isArray()) {
+            this.fieldNames = new ArrayList<>(schemaNode.size());
             for (JsonNode fieldNme : schemaNode) {
                 fieldNames.add(fieldNme.asText());
             }
+        } else {
+            this.fieldNames = Collections.emptyList();
         }
     }
 

src/main/java/com/networknt/schema/UnionTypeValidator.java

@@ -31,7 +31,7 @@
 public class UnionTypeValidator extends BaseJsonValidator implements JsonValidator {
     private static final Logger logger = LoggerFactory.getLogger(UnionTypeValidator.class);
 
-    private final List<JsonValidator> schemas = new ArrayList<>();
+    private final List<JsonValidator> schemas;
     private final String error;
 
     public UnionTypeValidator(SchemaLocation schemaLocation, JsonNodePath evaluationPath, JsonNode schemaNode, JsonSchema parentSchema, ValidationContext validationContext) {
@@ -41,21 +41,24 @@ public UnionTypeValidator(SchemaLocation schemaLocation, JsonNodePath evaluation
         String sep = "";
         errorBuilder.append('[');
 
-        if (!schemaNode.isArray())
+        if (!schemaNode.isArray()) {
             throw new JsonSchemaException("Expected array for type property on Union Type Definition.");
+        }
 
         int i = 0;
+        this.schemas = new ArrayList<>(schemaNode.size());
         for (JsonNode n : schemaNode) {
             JsonType t = TypeFactory.getSchemaNodeType(n);
             errorBuilder.append(sep).append(t);
             sep = ", ";
 
-            if (n.isObject())
+            if (n.isObject()) {
                 schemas.add(validationContext.newSchema(schemaLocation.append(ValidatorTypeCode.TYPE.getValue()),
                         evaluationPath.append(ValidatorTypeCode.TRUE.getValue()), n, parentSchema));
-            else
-                schemas.add(new TypeValidator(schemaLocation.append(i), evaluationPath.append(i), n, parentSchema, validationContext));
-
+            } else {
+                schemas.add(new TypeValidator(schemaLocation.append(i), evaluationPath.append(i), n, parentSchema,
+                        validationContext));
+            }
             i++;
         }