Fix page size retrieval in Main.java

Author: rohitpaulk

compiled_starters/java/src/main/java/Main.java

@@ -19,8 +19,9 @@ public static void main(String[] args){
         try {
           byte[] header = Files.readAllBytes(Path.of(databaseFilePath));
 
-          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order
-          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort();
+          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order.
+          // '& 0xFFFF' is used to convert the signed short to an unsigned int.
+          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort() & 0xFFFF;
 
           // You can use print statements as follows for debugging, they'll be visible when running tests.
           System.out.println("Logs from your program will appear here!");

solutions/java/01-init/code/src/main/java/Main.java

@@ -19,8 +19,9 @@ public static void main(String[] args){
         try {
           byte[] header = Files.readAllBytes(Path.of(databaseFilePath));
 
-          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order
-          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort();
+          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order.
+          // '& 0xFFFF' is used to convert the signed short to an unsigned int.
+          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort() & 0xFFFF;
 
           System.out.println("database page size: " + pageSize);
         } catch (IOException e) {

solutions/java/01-init/diff/src/main/java/Main.java.diff

@@ -1,4 +1,4 @@
-@@ -1,37 +1,33 @@
+@@ -1,38 +1,34 @@
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
@@ -20,8 +20,9 @@
          try {
            byte[] header = Files.readAllBytes(Path.of(databaseFilePath));
 
-           // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order
-           int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort();
+           // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order.
+           // '& 0xFFFF' is used to convert the signed short to an unsigned int.
+           int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort() & 0xFFFF;
 
 -          // You can use print statements as follows for debugging, they'll be visible when running tests.
 -          System.out.println("Logs from your program will appear here!");

starter_templates/java/src/main/java/Main.java

@@ -19,8 +19,9 @@ public static void main(String[] args){
         try {
           byte[] header = Files.readAllBytes(Path.of(databaseFilePath));
 
-          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order
-          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort();
+          // The page size is stored at the 16th byte offset, using 2 bytes in big-endian order.
+          // '& 0xFFFF' is used to convert the signed short to an unsigned int.
+          int pageSize = ByteBuffer.wrap(header).order(ByteOrder.BIG_ENDIAN).position(16).getShort() & 0xFFFF;
 
           // You can use print statements as follows for debugging, they'll be visible when running tests.
           System.out.println("Logs from your program will appear here!");