可以尝试使用 ANTLR4 而非 ANTLR3，或者使用更高效的 Python 解析器。

使用 ANTLR4 的代码示例：

from antlr4 import *
from Java8Lexer import Java8Lexer
from Java8Parser import Java8Parser

class MyListener(ParseTreeListener):
    def enterMethodDeclaration(self, ctx: Java8Parser.MethodDeclarationContext):
        print("Found method: " + ctx.Identifier().getText())

def parse_java_file(file_path):
    input_stream = FileStream(file_path)
    lexer = Java8Lexer(input_stream)
    stream = CommonTokenStream(lexer)
    parser = Java8Parser(stream)

    tree = parser.compilationUnit()
    listener = MyListener()
    walker = ParseTreeWalker()
    walker.walk(listener, tree)

换用更高效的 Python 解析器的代码示例：

from javalang import parse

def parse_java_file(file_path):
    with open(file_path, 'r') as f:
        java_code = f.read()

    tree = parse.parse(java_code)

    for path, node in tree.filter(javalang.tree.MethodDeclaration):
        print("Found method: " + node.name)