[Java] Add @javax.annotation.Nonnull to required getters (#9593)

* Add @javax.annotation.Nonnull to required getters

* Add updated samples

* Consider the nullable constraint

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/Animal.java

@@ -56,6 +56,7 @@ public class Animal implements Parcelable {
    * Get className
    * @return className
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public String getClassName() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/Category.java

@@ -75,6 +75,7 @@ public class Category implements Parcelable {
    * Get name
    * @return name
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public String getName() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/EnumTest.java

@@ -280,6 +280,7 @@ public class EnumTest implements Parcelable {
    * Get enumStringRequired
    * @return enumStringRequired
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public EnumStringRequiredEnum getEnumStringRequired() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/FormatTest.java

@@ -180,6 +180,7 @@ public class FormatTest implements Parcelable {
    * maximum: 543.2
    * @return number
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public BigDecimal getNumber() {
@@ -275,6 +276,7 @@ public class FormatTest implements Parcelable {
    * Get _byte
    * @return _byte
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public byte[] getByte() {
@@ -320,6 +322,7 @@ public class FormatTest implements Parcelable {
    * Get date
    * @return date
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public LocalDate getDate() {
@@ -388,6 +391,7 @@ public class FormatTest implements Parcelable {
    * Get password
    * @return password
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public String getPassword() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/Name.java

@@ -61,6 +61,7 @@ public class Name implements Parcelable {
    * Get name
    * @return name
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public Integer getName() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/Pet.java

@@ -169,6 +169,7 @@ public class Pet implements Parcelable {
    * Get name
    * @return name
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "doggie", required = true, value = "")
 
   public String getName() {
@@ -196,6 +197,7 @@ public class Pet implements Parcelable {
    * Get photoUrls
    * @return photoUrls
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public Set<String> getPhotoUrls() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/TypeHolderDefault.java

@@ -67,6 +67,7 @@ public class TypeHolderDefault implements Parcelable {
    * Get stringItem
    * @return stringItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public String getStringItem() {
@@ -89,6 +90,7 @@ public class TypeHolderDefault implements Parcelable {
    * Get numberItem
    * @return numberItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public BigDecimal getNumberItem() {
@@ -111,6 +113,7 @@ public class TypeHolderDefault implements Parcelable {
    * Get integerItem
    * @return integerItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public Integer getIntegerItem() {
@@ -133,6 +136,7 @@ public class TypeHolderDefault implements Parcelable {
    * Get boolItem
    * @return boolItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public Boolean getBoolItem() {
@@ -160,6 +164,7 @@ public class TypeHolderDefault implements Parcelable {
    * Get arrayItem
    * @return arrayItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(required = true, value = "")
 
   public List<Integer> getArrayItem() {

samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/model/TypeHolderExample.java

@@ -71,6 +71,7 @@ public class TypeHolderExample implements Parcelable {
    * Get stringItem
    * @return stringItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "what", required = true, value = "")
 
   public String getStringItem() {
@@ -93,6 +94,7 @@ public class TypeHolderExample implements Parcelable {
    * Get numberItem
    * @return numberItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "1.234", required = true, value = "")
 
   public BigDecimal getNumberItem() {
@@ -115,6 +117,7 @@ public class TypeHolderExample implements Parcelable {
    * Get floatItem
    * @return floatItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "1.234", required = true, value = "")
 
   public Float getFloatItem() {
@@ -137,6 +140,7 @@ public class TypeHolderExample implements Parcelable {
    * Get integerItem
    * @return integerItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "-2", required = true, value = "")
 
   public Integer getIntegerItem() {
@@ -159,6 +163,7 @@ public class TypeHolderExample implements Parcelable {
    * Get boolItem
    * @return boolItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "true", required = true, value = "")
 
   public Boolean getBoolItem() {
@@ -186,6 +191,7 @@ public class TypeHolderExample implements Parcelable {
    * Get arrayItem
    * @return arrayItem
   **/
+  @javax.annotation.Nonnull
   @ApiModelProperty(example = "[0, 1, 2, 3]", required = true, value = "")
 
   public List<Integer> getArrayItem() {