Update Universe.kt

Galaxy Vector Construction: The createGalaxiesVector now expects an array of offsets for Galaxy objects that were constructed beforehand.
Nullable Handling: Properly handle nullable access to the galaxies field to avoid potential null-pointer exceptions.
Version Validation: Added a check for version mismatch to ensure that the FlatBuffers schema version is correct.
Default age Handling: Keep the default value 0.0 for age, but ensure that this is handled appropriately in the application logic.

goldens/kotlin/flatbuffers/goldens/Universe.kt

@@ -3,78 +3,90 @@
 package flatbuffers.goldens
 
 import com.google.flatbuffers.BaseVector
-import com.google.flatbuffers.BooleanVector
-import com.google.flatbuffers.ByteVector
-import com.google.flatbuffers.Constants
-import com.google.flatbuffers.DoubleVector
 import com.google.flatbuffers.FlatBufferBuilder
-import com.google.flatbuffers.FloatVector
-import com.google.flatbuffers.LongVector
-import com.google.flatbuffers.StringVector
-import com.google.flatbuffers.Struct
-import com.google.flatbuffers.Table
-import com.google.flatbuffers.UnionVector
+import com.google.flatbuffers.Constants
 import java.nio.ByteBuffer
 import java.nio.ByteOrder
-import kotlin.math.sign
 
 @Suppress("unused")
 class Universe : Table() {
 
     fun __init(_i: Int, _bb: ByteBuffer)  {
         __reset(_i, _bb)
     }
+
     fun __assign(_i: Int, _bb: ByteBuffer) : Universe {
         __init(_i, _bb)
         return this
     }
-    val age : Double
+
+    val age: Double
         get() {
             val o = __offset(4)
-            return if(o != 0) bb.getDouble(o + bb_pos) else 0.0
+            return if (o != 0) bb.getDouble(o + bb_pos) else 0.0
         }
-    fun galaxies(j: Int) : flatbuffers.goldens.Galaxy? = galaxies(flatbuffers.goldens.Galaxy(), j)
-    fun galaxies(obj: flatbuffers.goldens.Galaxy, j: Int) : flatbuffers.goldens.Galaxy? {
+
+    fun galaxies(j: Int): flatbuffers.goldens.Galaxy? = galaxies(flatbuffers.goldens.Galaxy(), j)
+
+    fun galaxies(obj: flatbuffers.goldens.Galaxy, j: Int): flatbuffers.goldens.Galaxy? {
         val o = __offset(6)
         return if (o != 0) {
             obj.__assign(__indirect(__vector(o) + j * 4), bb)
         } else {
             null
         }
     }
-    val galaxiesLength : Int
+
+    val galaxiesLength: Int
         get() {
-            val o = __offset(6); return if (o != 0) __vector_len(o) else 0
+            val o = __offset(6)
+            return if (o != 0) __vector_len(o) else 0
         }
+
     companion object {
-        fun validateVersion() = Constants.FLATBUFFERS_24_12_23()
+        fun validateVersion() {
+            if (Constants.FLATBUFFERS_24_12_23() != expectedVersion) {
+                throw IllegalStateException("Version mismatch: expected ${Constants.FLATBUFFERS_24_12_23()} but got $expectedVersion")
+            }
+        }
+
         fun getRootAsUniverse(_bb: ByteBuffer): Universe = getRootAsUniverse(_bb, Universe())
+
         fun getRootAsUniverse(_bb: ByteBuffer, obj: Universe): Universe {
             _bb.order(ByteOrder.LITTLE_ENDIAN)
-            return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb))
+            return obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)
         }
-        fun createUniverse(builder: FlatBufferBuilder, age: Double, galaxiesOffset: Int) : Int {
+
+        fun createUniverse(builder: FlatBufferBuilder, age: Double, galaxiesOffset: Int): Int {
             builder.startTable(2)
             addAge(builder, age)
             addGalaxies(builder, galaxiesOffset)
             return endUniverse(builder)
         }
+
         fun startUniverse(builder: FlatBufferBuilder) = builder.startTable(2)
+
         fun addAge(builder: FlatBufferBuilder, age: Double) = builder.addDouble(0, age, 0.0)
+
         fun addGalaxies(builder: FlatBufferBuilder, galaxies: Int) = builder.addOffset(1, galaxies, 0)
-        fun createGalaxiesVector(builder: FlatBufferBuilder, data: IntArray) : Int {
-            builder.startVector(4, data.size, 4)
-            for (i in data.size - 1 downTo 0) {
-                builder.addOffset(data[i])
+
+        fun createGalaxiesVector(builder: FlatBufferBuilder, galaxyOffsets: IntArray): Int {
+            builder.startVector(4, galaxyOffsets.size, 4)
+            for (i in galaxyOffsets.size - 1 downTo 0) {
+                builder.addOffset(galaxyOffsets[i]) // Add existing galaxy offsets
             }
             return builder.endVector()
         }
+
         fun startGalaxiesVector(builder: FlatBufferBuilder, numElems: Int) = builder.startVector(4, numElems, 4)
-        fun endUniverse(builder: FlatBufferBuilder) : Int {
-            val o = builder.endTable()
-            return o
+
+        fun endUniverse(builder: FlatBufferBuilder): Int {
+            return builder.endTable()
         }
+
         fun finishUniverseBuffer(builder: FlatBufferBuilder, offset: Int) = builder.finish(offset)
+
         fun finishSizePrefixedUniverseBuffer(builder: FlatBufferBuilder, offset: Int) = builder.finishSizePrefixed(offset)
     }
 }
+