Revert "throw exception rather 'return null'"

This reverts commit 4ef7160.

Author: aqni

vector/src/main/java/org/apache/arrow/vector/LargeVarBinaryVector.java

@@ -98,7 +98,7 @@ public MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     final long startOffset = getStartOffset(index);
     final long dataLength = getEndOffset(index) - startOffset;

vector/src/main/java/org/apache/arrow/vector/LargeVarCharVector.java

@@ -102,7 +102,7 @@ public Types.MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     final long startOffset = getStartOffset(index);
     final long dataLength = getEndOffset(index) - startOffset;

vector/src/main/java/org/apache/arrow/vector/VarBinaryVector.java

@@ -97,7 +97,7 @@ public MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     final int startOffset = getStartOffset(index);
     final int dataLength = getEndOffset(index) - startOffset;

vector/src/main/java/org/apache/arrow/vector/VarCharVector.java

@@ -99,7 +99,7 @@ public MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     final int startOffset = getStartOffset(index);
     final int dataLength = getEndOffset(index) - startOffset;

vector/src/main/java/org/apache/arrow/vector/ViewVarBinaryVector.java

@@ -97,7 +97,7 @@ public MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     return getData(index);
   }

vector/src/main/java/org/apache/arrow/vector/ViewVarCharVector.java

@@ -101,7 +101,7 @@ public MinorType getMinorType() {
   public byte[] get(int index) {
     assert index >= 0;
     if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
-      throw new IllegalStateException("Value at index is null");
+      return null;
     }
     return getData(index);
   }