diff --git a/includes/utils/AutoloadGenerator.php b/includes/utils/AutoloadGenerator.php
index 9cf8cab5db7..dd1a38a84a7 100644
--- a/includes/utils/AutoloadGenerator.php
+++ b/includes/utils/AutoloadGenerator.php
@@ -126,45 +126,78 @@ class AutoloadGenerator {
 	 *  developers towards the appropriate way to update the autoload.
 	 */
 	public function generateAutoload( $commandName = 'AutoloadGenerator' ) {
-		$content = array();
 
-		// We need to generate a line each rather than exporting the
-		// full array so __DIR__ can be prepended to all the paths
-		$format = "%s => __DIR__ . %s,";
-		foreach ( $this->classes as $path => $contained ) {
-			$exportedPath = var_export( $path, true );
-			foreach ( $contained as $fqcn ) {
+		// We need to check whether an extenson.json exists or not, and
+		// incase it doesn't, update the autoload.php file.
+
+		if ( file_exists( $this->basepath . '/extension.json' ) ) {
+			require_once __DIR__ . '/../../includes/json/FormatJson.php';
+			$key = 'AutoloadClasses';
+			$json = FormatJson::decode( file_get_contents( $this->basepath
+				. '/extension.json' ), true );
+			unset( $json[$key] );
+			// Inverting the key-value pairs so that they become of the
+			// format class-name : path when they get converted into json.
+			foreach ( $this->classes as $path => $contained ) {
+				foreach ( $contained as $fqcn ) {
+
+					// Using substr to remove the leading '/'
+					$json[$key][$fqcn] = substr( $path, 1 );
+				}
+			}
+			foreach ( $this->overrides as $path => $fqcn ) {
+
+				// Using substr to remove the leading '/'
+				$json[$key][$fqcn] = substr( $path, 1 );
+			}
+
+			// Sorting the list of autoload classes.
+			ksort( $json[$key] );
+
+			// Update extension.json, using constants for the required
+			// formatting.
+			file_put_contents( $this->basepath . '/extension.json',
+				FormatJson::encode( $json, true ) . "\n" );
+		} else {
+			$content = array();
+
+			// We need to generate a line each rather than exporting the
+			// full array so __DIR__ can be prepended to all the paths
+			$format = "%s => __DIR__ . %s,";
+			foreach ( $this->classes as $path => $contained ) {
+				$exportedPath = var_export( $path, true );
+				foreach ( $contained as $fqcn ) {
+					$content[$fqcn] = sprintf(
+						$format,
+						var_export( $fqcn, true ),
+						$exportedPath
+					);
+				}
+			}
+
+			foreach ( $this->overrides as $fqcn => $path ) {
 				$content[$fqcn] = sprintf(
 					$format,
 					var_export( $fqcn, true ),
-					$exportedPath
+					var_export( $path, true )
 				);
 			}
-		}
 
-		foreach ( $this->overrides as $fqcn => $path ) {
-			$content[$fqcn] = sprintf(
-				$format,
-				var_export( $fqcn, true ),
-				var_export( $path, true )
-			);
-		}
+			// sort for stable output
+			ksort( $content );
 
-		// sort for stable output
-		ksort( $content );
+			// extensions using this generator are appending to the existing
+			// autoload.
+			if ( $this->variableName === 'wgAutoloadClasses' ) {
+				$op = '+=';
+			} else {
+				$op = '=';
+			}
 
-		// extensions using this generator are appending to the existing
-		// autoload.
-		if ( $this->variableName === 'wgAutoloadClasses' ) {
-			$op = '+=';
-		} else {
-			$op = '=';
-		}
-
-		$output = implode( "\n\t", $content );
-		file_put_contents(
-			$this->basepath . '/autoload.php',
-			<<<EOD
+			$output = implode( "\n\t", $content );
+			file_put_contents(
+				$this->basepath . '/autoload.php',
+				<<<EOD
 <?php
 // This file is generated by $commandName, do not adjust manually
 // @codingStandardsIgnoreFile
@@ -175,9 +208,9 @@ global \${$this->variableName};
 );
 
 EOD
-		);
+			);
+		}
 	}
-
 	/**
 	 * Ensure that Unix-style path separators ("/") are used in the path.
 	 *